SilentElkOfYesterday's teacher actually was most likely 100% dead on the money right. Beliefs like that were based on the ancient greek theory (promoted later by Galen) of the four humours, which tried to explain the workings of the human body based on a balance of four fluids or humours. Frequent ejaculation (among many, many other things), it was believed, could destroy that balance and make a person ill or even dead.