the act of brushing your teeth while taking a shiton the can. it is a great way to multi-task for you not only save time by brushing your teeth and crapping, but you can also spit the backwash of your tooth paste and water into the the toilet once you are done then flush it down all together which makes a lovely mint brown swirl known as the "sewage rainbow"
phone conversation "Dude come on we gotta go hurry up im waiting outside"
When you forget about the existence of something or someone. This happens more often than not when you're high, due to the impact on short-term memory.
Bill: "Hey, did Jack brumshit you the other day?"
Ted: "Yeah, he said to me 'I forgot you even existed.' He totally brumshat me."