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Concept: Sexual stimulation


During sexual stimulation, some women report the discharge of a noticeable amount of fluid from the urethra, a phenomenon also called “squirting.” To date, both the nature and the origin of squirting remain controversial. In this investigation, we not only analyzed the biochemical nature of the emitted fluid, but also explored the presence of any pelvic liquid collection that could result from sexual arousal and explain a massive fluid emission.

Concepts: Sexual intercourse, Female, Gender, Human sexuality, Orgasm, Penis, Sexual arousal, Sexual stimulation


WHAT’S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Genital secretions during female orgasm (female ejaculation) have been a matter of controversy for centuries. Scientific work on this essential part of female sexual function has been able to differentiate between female ejaculation, urinary incontinence and vaginal transudate. According to earlier studies, less than 50% of women actually do ejaculate during sexual stimulation. Few affected women discuss female ejaculation with their physician - partly because of its physiological nature, partly through embarrassment. To gain knowledge on the characteristics of female ejaculation and its impact on women’s sexual lives, an online questionnaire has been designed and published internationally. In this way, data from 320 women who perceive ejaculation could be acquired. Most women and their partners perceive female ejaculation as an enrichment of their sexual lives. OBJECTIVE: To study characteristics of female ejaculation as perceived by healthy women. To evaluate whether fluid emission during sexual activity has an impact on women’s or their partners' sexual lives. MATERIALS AND METHODS: An online questionnaire consisting of 23 questions addressing the participants' characteristics, aspects of perceived female ejaculation, and its impact on women’s and their partners' lives was published internationally on various online platforms. RESULTS: Over a period of 18 months, 320 women from all over the world were included in the study (excluding women below the age of 18 years and double entries). The women’s mean age was 34.1 years (±11.1) and their mean age at first ejaculation was 25.4 years. Most women ejaculate a few times a week. The volume of ejaculation is approximately 2 oz (29.1%), and the fluid is usually clear as water (83.1%). For most women (78.8%) and their partners (90.0%), female ejaculation is an enrichment of their sexual lives, whereas 14 women (4.4%) stated that their partners were unaware of their potential ejaculation. CONCLUSIONS: Perceived female ejaculation - and its onset - occurs in women of all ages. Most women who ejaculate do so on a regular basis. Female ejaculation is an enrichment of the sexual lives of women as well as their partners.

Concepts: Sexual intercourse, Human sexuality, Orgasm, Ejaculation, Penis, Masturbation, Female ejaculation, Sexual stimulation


Background: Previous studies have associated men who experience condom-associated erection problems (CAEP) with incomplete condom use and/or foregoing using condoms altogether. However, how men respond to CAEP and what they attribute CAEP to, remains unclear. Understanding young men’s CAEP responses and attributions could help improve sexually transmissible infections (STI)/HIV prevention programs and interventions. Methods: Behavioural responses to, and attributions for, CAEP during application (CAEP-Application) and/or during penile-vaginal intercourse (CAEP-PVI) were reported using an online questionnaire by 295 young, heterosexual men (aged 18-24 years) who were recruited via social media websites and university Listservs across major cities in the Midwestern USA. Results: Behavioural responses to CAEP-Application included receiving oral or manual stimulation, stimulating a partner, self-stimulation, foregoing condom use and applying the condom after starting intercourse. Attributions for CAEP-Application included: distraction, fit and feel problems, application taking too long and having consumed too much alcohol. Behavioural responses to CAEP-PVI included increasing the intensity of intercourse, removing the condom to receive oral or manual stimulation and removing condom and continuing intercourse. Attributions for CAEP-PVI included: lack of sensation, taking too long to orgasm, not being ‘turned on’ enough, fit and feel problems and partner-related factors. Conclusions: Men who report CAEP respond with both STI/HIV risk-reducing and potentially risk-increasing behaviours (e.g. forgoing condom use). Men attribute their experiences to a wide range of individual- and partner-level factors. Addressing men’s CAEP behavioural responses and attributions may increase the efficacious value of condom programs and STI/HIV prevention interventions - particularly among men who experience CAEP.

Concepts: AIDS, Sexual intercourse, Human sexual behavior, Human behavior, Chlamydia infection, Condom, Syphilis, Sexual stimulation


Within the literature individuals who use the internet to facilitate the sexual abuse of a minor are generally classified as being fantasy or contact driven. Classification is based upon the intended location for sexual climax: fantasy driven individuals aim to reach sexual climax online, whereas contact driven individuals target minors to achieve physical sex offline. This review systematically investigates whether there is an empirical basis for the distinction between these two proposed discrete types. Comparison of tactics and behaviour are considered to examine whether the contact vs. fantasy distinction is useful. A two-stage literature selection process, considered against pre-determined inclusion criteria, identified a total of twenty-two studies. As methodological heterogeneity limited the ability to conduct pooled analysis, a narrative synthesis of data employing an interpretive approach was conducted. This showed that the contact and fantasy distinction is ambiguous, given that both groups engage in online behaviours that provide them with online sexual gratification that can also lead to offline contact. Furthermore, no clear pattern of behaviour was found to define contact and fantasy individuals idiosyncratically. The European Online Grooming Project typology is thus proposed as a better representation of this behaviour; intimacy seeking, adaptable and hypersexualized groups. The distinction between these groups focuses primarily on the intensity of the relationship, acknowledging that sexual abuse can occur with or without offline contact. This review also highlights the need for larger, methodologically robust studies that examine the behaviour of online child sexual offenders.

Concepts: Sexual intercourse, Sex offender, Child sexual abuse, Human sexual behavior, Orgasm, Pleasure, Typology, Sexual stimulation


Orgasm is one of the most intense pleasures attainable to an organism, yet its underlying mechanisms remain poorly understood. On the basis of existing literatures, this article introduces a novel mechanistic model of sexual stimulation and orgasm. In doing so, it characterizes the neurophenomenology of sexual trance and climax, describes parallels in dynamics between orgasms and seizures, speculates on possible evolutionary origins of sex differences in orgasmic responding, and proposes avenues for future experimentation. Here, a model is introduced wherein sexual stimulation induces entrainment of coupling mechanical and neuronal oscillatory systems, thus creating synchronized functional networks within which multiple positive feedback processes intersect synergistically to contribute to sexual experience. These processes generate states of deepening sensory absorption and trance, potentially culminating in climax if critical thresholds are surpassed. The centrality of rhythmic stimulation (and its modulation by salience) for surpassing these thresholds suggests ways in which differential orgasmic responding between individuals-or with different partners-may serve as a mechanism for ensuring adaptive mate choice. Because the production of rhythmic stimulation combines honest indicators of fitness with cues relating to potential for investment, differential orgasmic response may serve to influence the probability of continued sexual encounters with specific mates.

Concepts: Sexual intercourse, Human sexual behavior, Human sexuality, Orgasm, Sexual arousal, Masturbation, Sexual stimulation, Human sexual response cycle


We confirmed ejaculation as a result of manual stimulation in a lar gibbon, and attempted to cryopreserve the semen using TES-Tris-egg yolk-based (TTE) extender. After measuring the amount of semen (g), we first diluted the semen with TTE extender, and calculated sperm concentration (sperm/ml), total sperm count (sperm), and progressive sperm motility (%). Then, we cooled diluted semen slowly to 4 °C over 2 h, and added an equal volume of secondary extender containing glycerol over 30 min. Finally, we flash-froze the semen solution by plunging into liquid nitrogen. In addition, we freeze-thawed the solution to determine the recovery rate of the motile sperm. Collection of semen was successful on four of the five occasions. The median (min-max) quantity of ejaculate was 0.19 g (0.09-0.26 g), the median sperm concentration was 1.38 × 10(9) sperm/ml (1.20-1.53 × 10(9) sperm/ml), and the median total sperm count was 0.26 × 10(9) sperm (0.11-0.40 × 10(9) sperm). Moreover, the median sperm motility immediately after ejaculation was 65 % (60-75 %), the median sperm motility after freeze-thawing was 30 % (25-35 %), and the median recovery rate was 42.3 % (40.0-58.3 %). We were able to (1) collect semen from a lar gibbon by manual stimulation, (2) reveal andrological findings regarding semen characteristics, and (3) preserve the genetic resource using TTE cryopreservation.

Concepts: Sperm, Semen analysis, Fertility, Semen, Ejaculation, Gibbon, Sexual stimulation, Lar Gibbon


Sexual behavior in rodents is modulated by the olfactory system. The olfactory bulb (OB) is a structure that undergoes continues neurogenesis in adulthood. We have previously shown that 15 days after males rats pace the sexual interaction and ejaculate 1 or 3 times, there is an increase in the density of new cells that reach the accessory olfactory bulb (AOB). The aim of the present study was to evaluate if sexual behavior in male rats increases the density of new neurons that survive 45 days after sexual behavior in the AOB and in the main OB (MOB). Male rats were randomly divided in four groups: (1) Control (Ctr), males without sexual interaction; (2) Exposed (Exp), males only exposed to a sexually receptive female; (3) No pacing (NP), males that mated in conditions in which the female paced the sexual interaction; (4) One ejaculation (1E), males that paced the sexual interaction with a receptive female and ejaculated once; and (5) Three ejaculations (3E), males that paced the sexual interaction and were allowed to ejaculate three times. All males were injected with the DNA synthesis marker 5-bromo-2-deoxyuridine (BrdU), and were tested in one of the above conditions. 45 days later they were sacrificed, and the OBs were processed to identify new cells and evaluate if they had differentiated into neurons. Our data indicate that males that ejaculated three times showed an increase in the density of new cells that survive in the posterior part of the granular cell layer of the AOB and have more new neurons that the control group. However, no significant differences were found in the percentage of new cells that differentiate into neurons. No significant increase in the density of new cells was observed in the MOB. Our data show that pacing the sexual interaction until three ejaculations increases the density of new cells and neurons in the granular layer of the AOB, confirming that sexual behavior induces long-lasting plastic changes in the OB.

Concepts: Granule cell, Semen, Olfactory bulb, Human sexual behavior, Gamete, Orgasm, Ejaculation, Sexual stimulation


Prestimulation administered to a cow before attachment of the milking unit has historically been performed manually. Development of innovative milking technology has allowed manual stimulation to be replaced by mechanical forms of stimulation. Holstein cows (n=30) were enrolled in a crossover design to determine the effect of manual stimulation (forestripping and drying) and high-vibration pulsation on oxytocin profiles, milk yield, milk flow rates, incidence of delayed milk ejection causing bimodal milk flow curves, and residual milk in Holstein cows milked 3 times daily (3×). All cows were subjected to all treatments. Cows received manual (forestripping and drying) or mechanical (high-vibration pulsation) stimulation along with lag times of 0, 30, or 90 s for 21 consecutive milkings. Forestripping involved the manual removal of 2 streams of milk from each teat and drying of the teats. High-vibration pulsation involved increasing the pulsation cycles from 60 to 300 pulses/min and reducing the vacuum in the pulsation chamber to 20 kPa. The 5 treatments were (1) immediate attachment of the milking machine under normal pulsation (T0); (2) dip plus forestrip and drying with 30-s lag time (FD30); (3) dip plus forestrip and drying with 90-s lag time (FD90); (4) high-vibration pulsation for 30 s (HV30); and (5) high-vibration pulsation for 90 s (HV90). Milk yield per milking averaged 14.0kg and was significantly different among treatments; however, the maximum difference detected among treatments was 0.8kg/milking. Milking unit on-time, which represents the time when the milking unit is under normal pulsation and harvesting milk (excluding the high-vibration pulsation time of 30 or 90 s), was shortest (245 s) for cows subjected to 90 s of high-vibration pulsation (HV90) and ranged from 256 to 261 s for all other treatments. Milk harvest may have begun during high-vibration pulsation; however, only 0.13 and 0.32kg of milk was harvested during high-vibration pulsation for HV30 and HV90, respectively. The incidence of bimodal milk curves was lowest for FD90 (7%) and highest for T0 (21%). The somatic cell count was <72×10(3) cells/mL for all treatments. Residual milk obtained by giving 10 IU of oxytocin in the jugular vein followed by 2min of milking unit attachment represented 12 to 14% of the total milk and did not differ among treatments. Endogenous oxytocin profiles peaked between 12.4 and 18.3 pg/mL for all treatments, and the peak occurred sooner in manually stimulated cows; however, we detected no difference in oxytocin concentration beyond 2min after milking unit attachment. High-vibration pulsation elicited a similar oxytocin release when taking the start time of stimulation from manual stimulation or high vibration into consideration. Forestripping for visual observation of milk combined with the use of high-vibration stimulation may reduce variation in the milking routine. A predetermined lag time with minimal variation may be achieved via the time spent in high-vibration stimulation instead of a lag period dictated by milking personnel.

Concepts: Milk, Oxytocin, Cattle, Dairy farming, Lag, Manual transmission, Sexual stimulation


Premature ejaculation (PE) is commonly defined as ejaculation with minimal sexual stimulation before, on or shortly after penetration and before the person wishes it. PE can be either lifelong and present since first sexual experiences (primary), or acquired (secondary), beginning later (Godpodinoff ML. Premature ejaculation: clinical subgroups and etiology. J Sex Marital Ther 1989;15:130-4). Treatments include behavioural and pharmacological interventions.

Concepts: Medicine, The Canon of Medicine, Orgasm, Ejaculation, Penis, Premature ejaculation, Sexual dysfunction, Sexual stimulation


Since Antiquity, women who expulse a large quantity of liquid during sexual stimulation have remained a mystery. This phenomena is usually called “squirting”. Many physicians have proposed different explications, however, there are very few scientific publications and their conclusions are discordant. Today, squirting is fashionable in the media, and some recent studies have brought new information. Through medical publications, we present the conclusions concerning the origin and the nature of squirting, the psychological experience of these squirting women and the feelings of their partners.

Concepts: Time, Science, Woman, Orgasm, Ejaculation, Mass media, Female ejaculation, Sexual stimulation