Raspbelly

The action of placing one's lips against the skin of another's stomach and blowing, producing a fart like sound.

Basicall blowing a raspberry, but on the belly. Often called a zerbert.

"I got my kid with the loudest raspbelly ever yesterday!"

zerbert

When it's done in the stomach area, it becomes known as a raspbelly.

"I'm going to do the biggest, loudest, wettest raspbelly you've ever had!"

"You mean a zerbert?"

"No, I mean a raspbelly!"