English: Shown at 100%, 50%, and 10% speeds. Subject is a 44 year old Caucasian Male. Orgasm induced by manual self stimulation, showing externally the involuntary rhythmic contractions of the Anal Sphincters and Bulbospongiosus Muscle signifying Orgasm. Along with synchronized contractions of internal structures including the Prostate, Semen is expelled from the body via the Urethra. Here, fourteen (14) regular, rhythmic Anogenital contractions are visible beginning at 0:07, coinciding with the subject's perceived start of Orgasm. The first two contractions are the most rapid, then at even intervals two through five (2-5), then gradually more spaced apart with each subsequent contractions. Ejaculation began with the first contraction; the largest volume was expelled during contractions two through five (2-5), with moderate ejaculation continuing through at least the ninth contraction. Only nominal amounts of ejaculate are expelled with subsequent contractions. Numerous involuntary contractions from fifteen (15) onward (not shown) become more irregular and lacked significant Ejaculation, if any. Approximately 4.5ml of ejaculate was measured. Just before orgasm begins, you can see the Bulbospongiosis muscle and Anal sphincters relax (0:04) when orgasm becomes imminent. Once begun, the muscular/glandular contractions, and Ejaculation, cannot be stopped or controlled until these physiological processes resolve. https://psychology.fandom.com/wiki/Ejaculation