Definition
A group of three stupid people.
How People Actually Use It
When you slap a woman's breasts like Moe slaps Larry and Curly. A swipe from the side, hitting one boob then the other. Then back the other way. Then tapping the top quickly while saying "Woopwoopwoop" with an optional "Why I oughta".
"Tyler was so much fun in bed last night. He gave me the three stooges until my nipples were rock-hard and then fucked me to multiple orgasms."
Source: Urban Dictionary