To gyren is to assume that something is common knowledge but it really isn't. Along with that, to gyren is to assume something is commonly expected from people, but once again it really isn't.
During WWI the Marines fought with such ferocity and valor that they were called GI's. A marine doesnt want to be called a GI he wants to be called a Marine so they mixed the two to for Gyrene (GI-Marine)
The term used for when an erect penis gyrates like Elvis's pelvis. Few are known in the world to be able to gyrect.
Matt the Canadian: Did you hear what happened at last night's party?
Jamie: yeah, Greg was all up in that chick with a gyrection. He was gettin' his elvis pelvis on.
Patrick: Bitch please, mah dick's bigger anyways....