I sometimes wake up with a wet, sticky spot on my underwear or pajama pants. It's not urine, so what is it? – Stewart* Chances are that you had a "wet dream" — something that can be embarrassing and confusing, but is completely normal. A wet dream is when a guy ejaculates (or "cums") while he's sleeping. During ejaculation, semen (the fluid containing sperm) comes out of the penis and this is what you noticed on your underwear or pajama pants. Wet dreams usually happen during dreams that have sexual images. Sometimes guys wake up from a wet dream, but sometimes they sleep through it. Wet dreams begin during puberty when the body starts making more testosterone, a male hormone. Some guys may feel embarrassed or even guilty about having wet dreams. But they're are a normal part of growing up and you can't stop them from happening. Most guys have wet dreams at some point during puberty, and even sometimes as adults. Wet dreams usually happen less as guys get older, though. *Names have been changed to protect user privacy. Back to Articles Related Articles Is It Normal to Get Erections? If you've ever had an erection in an embarrassing situation, you've probably asked yourself this question. But erections are a perfectly normal function of the male body, especially in guys who are going through puberty. Read More Is My Penis Normal? Just about every guy wonders about the size of his penis at one time or another. Read More Male Reproductive System What makes up a guy's reproductive system and how does it develop? Find the answers to these questions and more. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.