To take a bath with a cat.
After a day of frolicking in the fields, she was excited to get clean by taking a catbath.
The act of licking somone over his or her entire body as a sexual favor.
Guy 1: Dude, did you end up getting Kelly that purse she wanted for her birthday?
Guy 2: Nah man, I was super low on cash so i gave her a catbath instead. She said it was the best present ever.
Guy 1: Damn, you two are getting pretty serious.
I could really use a catbath. I hope my girlfriend is in the mood to give me one tonight.