The idea of drinking a milkshake while taking a shit appeals to me. Ideally, right out of the metal cup that you mix it all up in, with a straw. Finding some resistance in the straw as you go. Waiting for all the stool to come out while you wait for all the shake to come in.
The simultaneous input/output is a rich and rewarding experience. Maybe some folks would want to have really differentiated input and output though, like this would only be pleasurable with really solid stool and really liquid milkshake. The more I think about it, the more appealing it is with a milkshake and stool consistency that closely mirror each other. One thing that seems worth differentiating is having a milkshake the temperature of feces exiting your body would be pretty straight up gross. And having freezer-temperature stool seems unpleasant.