This is a proper name for when you attempt to insert your nuts into a girl's ass. It is so named because it can be just as hard as keeping a dog in the tub while giving it a bath.
I tried like hell to pull off a Dog In A Bath Tub on Suzy, but her queaf threw my balance off.
A sexual act in which a male attempts to place his testicles into the asshole of his partner (preferably female but male-male action is possible also). Ideally, the asshole being to tight the testicles will repeatedly pop back out like a when you try to put a dog in a bath tub. The asshole should be well lubed and loose enough to allow partial testicle penetration. Not an ideal position for virgin or gaping assholes.
That girl is such a slut. Last night, she let me put the doggie in the bath tub!
The art of inserting one's testicles deftly into a slut's vagina. Then anal penetration via phallus follows.
This is said to be as difficult as giving to cats a bath.
Aidan, after months of practice, successfully got twocats in the bath tub with the woman of Tim's dreams.