In addition to all the group masturbation definitions,
The Circle Jerks are a hardcore punk band formed circa 1979 in Hermosa Beach, California. It was formed by Black Flag's original singer, Keith Morris, and future Bad Religion guitarist Greg Hetson. They were among the preeminent punk bands of the L.A. scene in the early 1980s.
After seeing the Circle Jerks show and getting our asses kicked in the pit, my friends and I participated in a circle jerk in John's van.
Essentially the Midwestern version of the Amish, but they utilize a bit more technology. Religious folks who live on farm communes, but due to the geography they use automobiles and a few other modern implements.
I was paid $500 dollars for my stud work last week at the Shaw Butte Hutterite colony. She was rather fugly, but I'll do what I can to keep them from getting too inbred.