Thunder-pumping

The act of vigorous masturbation, but only when it is so violent that anyone who hears it, assumes they are hearing rumpy-pumpy.

Person 1: I was totally thunder-pumping to your mom's Facebook last night
Person 2: ....

by JBizzle89 November 12, 2012

Thunder Pump

To hump someone as hard as you possibly can.

Mate, I thunder pumped that girl all night long!

by Johnny Bad May 25, 2008