It's great: Reimu is forced to wear a diaper which is humiliating, as she's not a baby anymore. Then when the poo-poo time comes she can't use the toilet and does an uneasy mr shit which takes us back to the first panel. Mindbreaking using yu's phisical features = double win. So simple, yet so effective.
Okay okay, I'll take it off for you.
But as a return, if this time you crap outside of the toilet, then it's 50 consecutive double-slap for you.
Got it?!