Buck Wild
Definition:

Buck Wild
1. For somebody or something to go crazy in some way. Can be used to describe a person going crazy or can be used in a sexual sense as well.
Description: "John went buck wild after I told him I wrecked his car."
Sexual Description: "We had buck wild sex last night!"
2.Crazy, insane looney, out of control.
3. To fight insanely, unrestrained.