Usually the way this ends up is, "Dude, you just jizzed on my balls! If you're gonna be on top, you gotta finish inside!"

Then the guy on the bottom pulls out and jizzes in the top guy's eye, just to get back at him.

Then it degenerates into a jizz fight, with both of them firing off jizz at point-blank range, like some kind of wild-west bar shootout. The poor girl is caught in the cross-fire dodging jizz rounds left and right!

Spurt!
Splat!
Aaaaaagh!
Jizzz!
Slap!
OOooow!
Squirt!

And so on...