File:Orgasm 020824 Measured Contractions and Ejaculation.webm

English: The External Physiological Orgasm response (Anogenital Muscular Contractions and Ejaculation) of 44 year old Caucasian male, induced by manual self stimulation, showing externally the involuntary rhythmic contractions of the Anal Sphincters and Bulbospongiosus Muscle at regular intervals. Along with synchronized contractions of internal structures including the Prostate, Semen is expelled from the body via the Urethra. Orgasm is shown first at 100% speed, and then at 25% speed. Here, sixteen (16) rhythmic involuntary muscular contractions of the Anus and surrounding structures are visible. Upon the subject perceiving Orgasm as imminent, stimulation was slowed, and minor involuntary contractions visible (in slow motion) at 0:46, 0:51, and 0:54 fill the Urethra with Semen, resulting in prominent expulsion of ejaculate with the first forceful contraction (onset of orgasm) at 0:08 (0:57 in slow motion), instead of the more typical second contraction, as the Semen needs to first make its way to the Urethral opening. The subject perceived orgasm to begin at approximately 0:07-0:08 (0:54-0:57), coinciding with visible physical response. The first four (4) more forceful yet irregular contractions signifying the moment of inevitability occur at 0:49, 0:52, 0:53 and 0:56 seconds. The first invountary muscular contractions of Orgasm begin at appx 0.57. Contractions one through four (1-4) are at fairly even intervals, gradually slowing incrementally after that. Ejaculation begins with the first contraction (0:08, 0:57); the largest volume was expelled during contractions one through three (1-3), with moderate semen expelled through at least the seventh (7th) contraction, though with gradually less force and volume. Nominal amount of semen is expelled with subsequent contractions, which are spaced at gradually longer intervals. Numerous involuntary Anogenital muscular contractions from the fifteenth (15th) contraction onward (not shown) become more irregular, and lacked significant volume of ejaculate, if any. A total of approximately 3.5ml of Semen was measured. Just before orgasm begins, you can see the Testicles retract toward the Abdominal cavity and relaxation of the Bulbospongiousus muscle and Anal Sphincters (0:04, 0:49) as Orgasm becomes imminent. When Orgasm begins, contractions and ejaculation are involuntary and cannot be stopped or controlled until the physiological processes resolve.