Has anyone played this game before?

So I used to play this game with my uncle but I can't remember the name of it. But it went like this.

He would choose a place on my body and try to fit as many fingers as he could in that place, and then I would do the same to him (I always won because my fingers were smaller).

I'm trying to explain it to my work friend, but then she called the police, so I'm just trying to show her that it's a normal game, but I can't find the name of it anywhere! Help please.