Nocturnal emission

Nocturnal emission is when a boy's body releases semen (which is the stuff that comes out of the penis during ejaculation) while he's asleep at night. It happens because his body is producing hormones that are getting ready for him to become a man. When he has a nocturnal emission, he might wake up with wet or sticky sheets, but it's completely normal and happens to most boys as they go through puberty.