A sound that represent the word goon or GDG. When you see someone who appears to be a goon, make an "Ewsh" sound and this will represent the level of goon that the person is. For higher level of goons, you exagerrate the word to "Eeeewwwwwwwwsssssh!"
The theory behind "Ewsh" is that someone walked in on a certain person who made the "Ewsh" sound and goon face while rubbin one out.
You're at a Steelers football game and you see someone wearing a Mark Breuner jersey with black tape over the 8, only exposing the number 7, with "Roethlis" written in black sharpie on duct tape next to Breuner spelling "Roethlisbreuner." You look at a buddy of yours and give an "Ewsh." Also when you see anyone with a mullet, "Ewsh" is a must.