you wellin

It means "your joking!" or "your kidding!". Suggesting that whatever the person said was unrealistic or just stupid.

Trey: I bet I could get a date with Beyoncé.
Mick: You wellin my nigga!

Kevin: Imma blow the school up.
Daiquawn: You wellin bruh!

by chacha_JOYask February 9, 2014