Balls on my ass is the ultimate Inside-Outside feeling. By that I mean, two things are happening simultaneously. To have a dick balls-deep in my pussy means that, by definition, I am being massaged as deeply inside me as possible by his dick. At the same time, his balls are rubbing and tickling the skin on my ass. It's a subtlety but anyone who takes a fucking with ball touches knows how wonderful that feeling is.
I would like to.
Marek