The 'flush' is a button to press to your left. You press it. Suddenly, two robotic hands appear from the wall and wrap around the girl's abdomen. Then, a vacuum-like tube places over the loli's pussy and ass. You look on with interest.
The hands massage and squeeze the child, making the human waste come out. The toilet girl, judging from her expressions and moans, really enjoys this. Once the waste gets moving, the tube start sucking it out. The sucking is quite noisy. You brave the noise as you realize that even when it's not a real toilet, flushing is still loud.
This doesn't bother the girl, she very much likes her puss getting sucked. After it was done, smaller tubes squirt non-toxic cleaning fluid in both holes, even in her mouth (the toilet-girls usually have a choice to swallow the fluid to clean their throats and stomachs, or they could spit it out).
The flushing process is over. You depart, was you hands and leave the bathroom.