cheesin: to grin insanely. Quite often after good news or a good getting into someone. If "pure" said in front of it, then a common Glaswegien saying emerges.
Not to be mistaken from the older sayin "cheesed off" used by middle aged people who still think that they are "hip"
The act of huffing or inhaling concentrated urine from a male feline. When male cats are marking their territory, they release concentrated, pure, and highly hallucinogenic urine. Hallucinations experienced from huffing "the cheese" cause intense visuals and out of body experiences. One may feel they are re-living the movie "Heavy Metal." For further reference watch the episode of South Park titled "Major Boobage."
"Dude, I'm cheesing my fucking brains out right now..."
"Dude, Nick is cheesing his fucking balls off right now."