A variation of the cunnilumpkin in which a woman receives cunnilingus while she deposits feces into the upper tank of a toilet. This is the female version of the blumpkin decker, and is far more difficult.
Intentional: For those rare women who find the smell of their lover's feces erotic, the reverse cunnilumpkin is the most exciting way to receive oral sex.
Accidental: My girlfriend loves it when I go down on her and chow box, and sometimes she can be so pushy about it. The other day I needed to crap so bad, but she told me to shut up and suck her vulva. Just as she was about to climax, I lost control of my bowels and dropped the whole load in my pants. It was a perfectly timed reverse cunnilumpkin, although I could have done without all the shit in my favorite khakis.