its when you shit in an aliensmouth, either an illegal, or the space kind
"yeah im fucking with an illegal, earlier i gave her a cosmic brownie"
"yeah i flew in space, and i met this freaky ass alien, yeah i gave her a cosmic brownie"
When an overly tan girl is wearing a skirt and no panties, slips and falls on an icydeck and gets her labia stuck on it. Like a tongue to a flagpole in the winter.
You should have seen Gina when she came out of the tanning salon that b**** slipped and fell and got a slippery twatbrownie