Corning on the cob 

When the penis is too big to fit inbetween someone's asscheeks or pussy flaps, so they have to sit on top of it like they would a horse, and slide up and down.

Joel: What the fuck are you doing, Courtney?!
Courtney: I'm corning on the cob, Joel!

*both laugh*

Corning on the cob by Jakercut August 18, 2016