What exactly happens during orgasm?
An orgasm is the experience of sexual climax that occurs upon ejaculation, when the penis expels semen in a sequence of pleasurable contractions, or spasms, that lead to release. The muscles supporting the vas deferens (the tube that transports semen for the testicles and up through the penis shaft) contract, pumping ejaculate through the penile tract for an ultimately pleasurable release of the tension that mounted during arousal and sexual penetration.