Ejaculation is when semen and sperm are released from the penis. It usually occurs when a man orgasms (climaxes). It happens during sex. It may also occur if the boy/man masturbates or someone else touches his penis. Ejaculation can also happen during sleep-called a wet dream. One ejaculation contains around 500 million sperm and each sperm can make a woman pregnant.
Attribution: Straight Talk Foundation