BIYM 

Balls In Ya Mouf.

Person 1: Hey, I wanted to talk to you about last night...
Person 2: Hey, you know what? BIYM! Okay? Last night never happened.

BIYM by K Wheezle May 25, 2004

BIYM 

BIYM stands for Balls. In. Your. Mouth. Its the perfect comeback and is always fun to use and say with your friends or even your parents.

"deez nuts in your mouth hahahaha"
"boy BIYM"
"what..."
"BALLS IN YOUR MOUTH HAHAHAH"

BIYM by asherinalol February 17, 2022

biym 

Balls in your mouth

“My newest Tinder hookup frequently verified with me that he wasn’t crossing any boundaries, and I was all for it; until, he mentioned biym. Not a fan.”

Or

Did the biym trick work with your boyfriend?

biym by Ibeliveinjustice January 8, 2020