Definitions by Hector whaller

Marsh 

When having heated sexual intercourse in the cowgirl position the male performes the "marsh" by grasping the back of the females head and bucking forcefully with his hips until the females head enters or pierces the headboard/wall behind.

I was having such heated sex last night that i totally marsh'd my girlfriend

Marsh by Hector whaller June 26, 2017