for when someone is sitting on their balls, like a puff.

wat

I think he means when a character has hyper balls, so big they're able to sit on top of them.

Kaeobais said:
I think he means when a character has hyper balls, so big they're able to sit on top of them.

yes

For images like this , this and this then yes, I could see ball_sitting as an ok tag. (It is a unique and easily definable position that just plain sitting does not cover, making it hard to find otherwise.)

Protip: Just make sure to also tag them with hyper_balls as needed. I'd imagine most ball_sitting pictures would need both tags because ball_sitting doesn't really apply to normal-sized balls (unless someone were to create a parody of it).