Mesubuta no Rakuin ~ Kachiku Choukyou Sareta Tsuma no Matsuro

When Hiroko Blackwater is expelled from school she takes revenge on her teacher's wife, Mayumi Kitahara, while Mr. Kitahara is in hospital. Bowel evacuation! Public exposure!

"Please stop... it's too humiliating!... I can't... Please, don't do... nooooo! NOOOOO!
Oh my god my sh*thole is about to burst! It's all coming out Here it comessss!!"

[From DLsite English]