look up any word, like sparkle pony:
The act of sticking a mars bar into ones vagina/anus/any other inappropriate cavity of the body besides the mouth, then eating it.
1. HER: "Hey you have a bit of chocolate in your teeth"

HIM: "Oh, yeah, I was just marsing my girlfriend."

2. HIM: "Wow, your vag tastes like mars bar."

HER: "Yeah, that would be because I was recently marsed."
by Hong Long September 26, 2009