Brony term, meaning breasts in the crotch area of a pony from the My Little Ponyfranchise, used in MLP fanart. They appear to be attached/grown from the top of the inside back legs, or slightly forward on the lower abdomen. God knows who thought this was a good idea.
Do not look up "crotchboobs" unless you want to be traumatised.
Brony FanArtist: Hey, I decided my current drawings of characters from a TV show designed for little girls weren't sexualised enough, so I decided to add BOOBS in the CROTCH area, crotchboobs, gettit?
You: All the ladies driving through the Highway must turn off their radios unless they wanna get fucked by Tom Crotchrane.
Me: I didn’t know that, but I do know Life Is a Highway and that’s a classic song.
"Listen, you ignorant crotchmonkoid... shut the fuck up and go back to making cave-paintings of Bam-Bam fisting Pebbles before I kick you in the spine."