A 'Gooch Assasin' is a man who takes pleasure in hand slapping the gooch of another man. A gooch assasin may or may not have acutal ninja skills. There are a particularly disturbing comunity of Gooch assasins who attack their prey when showering.
A perjorative term used to describe someone of the same gender who has invaded your personal space.
Walter the Gooch Assasin waited quietly in the wardrobe for Stuart to enter the hotel room and undress. As soon as Stuart was naked Walter cartwheeled across the room and slapped him right on his exposed gooch.
While Xavier was waiting in line Timothy pressed closer than Xavier felt comfortable with. To alert Timothy Xavier said "geez Timothy could you take a step back, you don't have to stand so close you gooch assasin!' Timothy got the point and backed it up.