Smellybutton 

A particularly foul belly button odor typical of overweight and under showered people. It's a form of fromunda cheese.

"I stuck my finger in her smellybutton on accident and couldn't pick my nose for a month.

Smellybutton by MAXTAXIN March 20, 2017

smellybutton 

A bellybutton that smells. What the hell else would it mean?

Stuck my finger in my bellybutton this morning. That shit stinks. I've got a smellybutton, son.

smellybutton by A Nice Chunk of Bernice June 24, 2010