Wikipedia
Hyperspermia
Hyperspermia is the medical term for when a male has an abnormally large ejaculate (or semen) volume. Males with hyperspermia usually have higher sex drives than males that do not. It is the opposite of hypospermia, and is generally defined in humans when the ejaculate is over 5.5 ml. Average output of hyperspermia males range from 5-50 ml per ejaculation and it can be produced over multiple ejaculations in a single sexual session. Three percent of males are able to have multiple ejaculations over any given time.