This morning the dog comes in from his morning routine and promptly settles in to cleaning himself. As regularly scheduled, I hear "oh, gross" and "Chewie's cleaning his penis pocket again. Eww!" from the kiddos. I always catch myself from wanting to call that 'penis pocket' a sheath. Don't know why. I have no idea if that is the technical body part name for it or not. But whenever I think of the word "sheath," I think of this scene from Gladiator. I can see into the future that I'll be some old grey hair with a male dog, chasing him around yelling "Sheath your sword!"
And that folks, is simply how my brain works.