The man custard that shoots from the penis when rubbing one out.
"That chick is so hot, when I get home I'm gonna pop off some knuckle babies. When doing so, she will tell me I am great, and I will believe her."
by tommyboy79 April 06, 2006
n. Male ejaculate resulting from masturbation
Lindsay Lohan posed naked for Playboy, and I gave birth to a knuckle baby.
by peo May 24, 2008
n. knucklebabies is the outcome a male gets after he roughs up his suspect (masterbates) and dosent release his sperm into a sock or something and it is all over the back of his hand.
I got home late lastnight and my wife was asleep,so i went to the computer and racked out a batch of knucklebabies.
by richard bellamy March 08, 2008
When jacking off and you sperm and sperm runs down the knuckles-
When flashjo3 whips out a batch of the knuckle babies
by MADDENGODOF813 April 25, 2011