When it's your birthday and a man congratulates you with his penis.
"Hi John, did you have a nice birthday this weekend?"
"Yeah, Tommy came and gave me birthday dick."
Happens the morning after a man ejaculates and doesn't wash his penis, the result is a penis covered in frosting, just like a birthday cake.
"Ewww Johnny, I'm not sucking your penis, you have that birthday dick!"
11👍 3👎
Birthday dick is a really large or satisfying penis. Usually only experienced every once in a while.
After a series of sexual letdowns, Emily finally got some much needed Birthday Dick.
4👍 10👎