This is a variation of gerbling for straight couples. The man goes about the usual preparation of sticking a gerbil up his rectum while the woman puts a snake in her vagina. The two then press their ass and vagina together and let the gerbil and snake fight. This is a very pleasurable act and is socially acceptable.
Dude, did you hear that Jerry and Martha are going to try Mousnaking? Wish I could get a girl to try that with me.