to have sex with a woman while wearing a clown costume. dervies from the combination of the words clown and humping.
"Dude did you have sex with my sister?"
"I clumped her ass, son"
by NiMo March 2, 2005
1. To have sex with a woman while wearing a clown costume.
2. A group of men, dressed up as clowns, arriving in a small car and running a train on one woman.
1. After a night of drinking, he would often end up clumping Ms. Sherman while eating a fried fish.
2. Yo, let's go clump that bitch.
by American, African November 18, 2007
the act of your balls clapping against someones ass durring buttsex
I was ridding that bitch bareback and couldent stop clumping
by gavin smith March 28, 2008
The act of hitting a person (usually across the face) with your penis.

The name comes from the sound it makes on impact.
First person to pass out tonight recieves a 'clumping'.
by Fitzyy November 8, 2006
(n) clump - someone who is being lame; a loser.
1. Why are you being such a clump? Snap out of it!

Origin: The classic definition of clump is a small lump of something, and is generally used when describing something nasty. Hence the connection with someone whose behavior is reminiscent of an unappealing little lump of something gross.
by jasa jalt May 19, 2010
Don and Bill totally clumped Hillary last night
by GL Taco Kitty November 27, 2019