armpit fuck 

When you stick your erect penis between another being's armpits (perferably sweaty) and hump them from the back. It is very arrousing, and very rare.

I was the first person to invent armpit fucking.

armpit fuck by Dan November 2, 2003

armpit fucking 

Getting a Roost greasy dick in your armpit

I love a good armpit fucking when I'm in Vegas

armpit fucking by Vine and grsin March 7, 2016