...a female dog looking at you rather nervously. She happens to be a rottweiler like you, and she is quite nervous looking, though your mind leaving through your bowels has made you oblivious to her feelings. All that you notice is her backside, where you can see her glistening genitals waiting for you. You retract your sheath, and take no time in letting yourself loose in her seeing as it's your first time - at least, your canine mind can't think of any time before this one. Your mate tries to pull out, but due to your knot she cannot help the matter. Eventually you finally reach climax.
At the same time, you can feel a small fart on your pubic area, and with a mighty rumble her anus expands, releasing a few pellets of poop. The pellets grow progressively larger, and with each one your mate becomes subtly more relaxed. The poop presses between the space between your crotch and her backside, creating a wild sensation in your brain that you try to get hard from despite having just ejeculated. Eventually, she releases a large stream of poop, as her remaining memories dissolve into mindless static in her brain, she becomes a retarded canine just like you. Subsequently, you feel your bowels pressing against your anus, and soon what little of your mind you had managed to reclaim from re-eating returns to brown sludge form along with that of the newly dumbed-down bitch.
The two of you united in mental ineptitude, you speed up the rate at which you drain your brains, and eventually, you take a massive look at the massive mountain you have created together. You decide to feast on the remains of your intelligence, and as you do, you feel your bladders signalling to you that they must be emptied. You both decide to comply, adding to the beautiful mess you have created, though what effects this has are not obvious to you. You start lapping up each other's waste products and before long, you are lost in the constant wave of joy to the point of noticing nothing else.