Michigan Purple Cow

When a guy who is able to lactate pumps up his nipples so that they are hard enough to penetrate his partner's anus or vagina. Then he proceeds to milk his inflated, purple udders into the anus or vagina while the partner milks semen out of his penis.

Dan: bro, I can see your fat ass nipples poking through your shirt, do you have an infection or something?

Bob: no, my girl gave me a Michigan Purple Cow last night.
Dan: dude that's fucked up