Ok first off, I've seen this as dog in the bathtub on this site and it is wrong. Dogs love water, cats hate water. Which is why when you are fucking a girl in the ass and manage to get your nuts up in her too it is called cat in the bathtub. Have you ever tried to keep a cat in a bathtub? It is about as tough as getting both nuts up a girls ass.
I was fucking me Julie in the ass last night and I stuffed my nuts in her ass too. Man, she thrashed around like a cat in a bathtub!
by Lebonier March 30, 2005
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When you are trying to stuff your nuts into a woman's fart pipe and as soon as you cram one in, the other nut pops out. Leaving you with only one nut in her asshole, but never two. - Very similar to trying to get two or more cats in a bathtub, one always escapes when trying to get the other in.

The only man to accomplish this feat is the very famous "aww nigga, nuts in the ass dick in da pussy" porn actor. Who overachieved the feat by keeping both nuts in a females asshole WHILE stuffing his giant dong in her vagina. Making us all feel inferior.
Man, I was trying to stuff my nutsack into Bertha's asshole, but all I got was cats in the bathtub
by TittyfaceJenkins March 28, 2016
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When a man tries to put his balls into somebody's asshole.
Example: I tried the cat in the bathtub last night. What is that? I tried to put my balls in my wife's ass. How was that? You every try putting a cat in the bathtub?
by Bathman0922 September 21, 2013
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A sexual act involving trying to push your testicles into someone's anal cavity during non-participatory guy on girl intercourse.
Usually done to try to get more enthusiastic involvement from your partner.
"Man, I was banging Shana the other night, and she was laying there all comatose, so I tried stuffing my balls in her ass... It was like trying to stick a cat in a bathtub..."
by Turd Ferguson 74 March 5, 2009
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