the art of escaping a party or bar you dont want to be at but are obligated to stay at by friends/ boyfriends/ girlfriends/co-workers, so you cant just leave and you are forced to be sneaky about it or be "shady." Shaddypeacing can come in many forms. you may jump out a bathroom window, say you have to go to your car to get something then never come back, or just creepily slide out the front or back door with no one noticing. either way, you leave with no explanation and never return. you are MIA for the rest of the night.
"i didnt wanna go home with that guy i met at the bar so i told him i had to go to the bathroom and shadypeaced out the back door"
"wow class today sucks, im thinking about signing my name in then shadypeacing immediately afterwards."