A catback exhaust is an exhaust system which has catalytic converters still in place. It refers to the components that run from the rear outlet of the catalytic converter all the way back to the exhaust tip.
A sexual position similar to doggy-style where the woman kneels with a flat back and forces you to thrust at an unnatural, upwards-diagonal angle much like the way cats perform intercourse.
A relation has been found between the amount of cats a woman owns and the likelihood she will attempt this horrendous sexual position.
Man: "Why are you kneeling in this uncomfortable position? this isn't doggy-style"
Woman: "What are you talking about?"
Man: "You must own a lot of cats.. I hate Catback-Style"
A: CATTACK!!!! *hits brother*
B: WTF IS WRONG WITH YOU KAREN!! THIS IS WHY I DONT TELL ANYONE AT SCHOOL WE ARE RELATED!! AND GET THE FUCK OUT OF MY ROOM!!!!!
A: *hisssss*
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).