And there’s always stank ho (that’s not oh knats!).
You’re becoming one of my favorite Dopers! I almost included that in the post but figured I’d already gotten too far off-base. I see David Alan Grier. Where’s that from?
PS: Urban Dictionary shows “scag” and “skag” to include the usages I remember from school days. They also have “skank” as a synonym.
It’s from In Living Color but I don’t remember the exact characters/skit. It tickled the funny bone of my best friend so much I’ll never forget it. 
The equivelant ILC moment for me was Jim Carrey doing Vanilla Ice “I’m a little teapot short and stout” and “Kick it!” and his sneaker goes flying. Bwah!
Oh, and
::blushes furiously 
Didn’t the ILC crowd do at least one movie? I never watched the TV show on a regular basis, but I have a distinct memory of the bit involving a T-shirt or something where “OH KNATS” gets reversed for the camera and whoever it is (as I recall, Grier) having a surprised look on his face as a result.
Pretty sure it wasn’t Amazon Women On The Moon, because I saw that again not too long ago. Grier and BB King and the “black man born with no soul” was the highlight of that.
The version I saw was one guy reading a paper and the other saying, You’re reading it backwards, it’s not Oh Knats, it’s Stank Ho.