Characters get fluid pumped into their ass with a hose, bulb, or hanging bag, often in a clinic-like setup or as a kinky “prep” before anal. The art tends to linger on the nozzle going in, the belly swelling or cramping, and the messy aftermath when the water leaks or shoots back out. It usually plays as a mix of medical fetish, humiliation, and intense focus on the ass being cleaned out and controlled.