Male sexual function has long been seen as a linear process: a man experiences sexual desire, blood pours into the penis, and it transforms from flaccid to extremely hard—an erection. Following a period of sexual arousal or activity, the male will experience ejaculation (the discharge of sperm), which is usually followed by orgasm (great pleasure and the release of neuromuscular tension). It is critical to recognize that ejaculation and orgasm are distinct processes that may occur separately. Men may also have ejaculation or orgasm without having an erection.