Taking a piss in the tub while taking a shower or a bath.
Lisa was tubipissin because she couldn't wait any longer while taking a bath. She had to take a shower afterwards because her pee was all over her body.
the act of taking a piss or shit while in the bath tub taking a shower or bath because of laziness. it also could be in a swimming pool, lake, or river.
tubipissin is easy to do when you're at the hotel because the damn tub isn't yours.