What has 2 arms, 2 legs, 2 eyes, 2 breasts for milking, and a hole to fill with my 9 inches?
A sexy female.
Listen up, genius. The joke sets you up to think of some kind of animal, but then BAM! It's just a crude way of describing a woman. Get it now? You probably don't. You probably think 9 inches is a measurement of intelligence, which, based on your humor, tracks.