If by toilet training you mean taking the shit it pooped out and injecting it back in...then yes...it's very very unique...
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Basically Anon has a KoMarisa and a KoReimu and the two just can't seem to poop in the toilet. So Anon, tired of it all, decides to inject their shit back inside them until they learn to poop in the toilet.
Marisa is up first and he does it seven times before she learned to poop in the toilet. Then comes Reimu...
When he held Reimu in his hand, he "missed" and hit her mamumamu instead, pumping all the shit into it, thus taking KoReimu's virginity as well as literally turning it into shit. But it didn't really matter to Anon since he was gonna neuter her in 3 days anyway.
He then says that he hopes this lesson would make her poop in the toilet properly. But as soon as he sets her down, she poops again in front of him. So he does it again, taking note that for some reason, Reimu types seem to place a high value on their virginity. Nevertheless he does this 12 times, each time re-injecting the shit into the mamumamu.
And in the end, they learn to use the toilet properly...i think, I kinda just skimmed the ending.