Post orgasmic illness syndrome (POIS) is a bizarre medical disorder that has only been observed in males.
Sufferers develop flu-like symptoms between a few minutes to a few hours after EVERY ejaculation, and these persist for a few days.
Symptoms include: fatigue, muscle pain, itching eyes, blocked nose, sore throat, impaired attention, and difficulty in formulating sentences.
Whether the ejaculation occurs from masturbation, sex, or spontaneously (like a wet dream) symptoms are the same.
POIS is very rare and only recently identified. Research is ongoing to investigate potential causes of POIS. Front runners are: allergic reaction (to seminal components or unknown proteins released during ejaculation), or psychosomatic.