I began writing a manga about my ideal sisters for myself,
Translation: he wrote this story to out himself as a submissive effeminate...
...and in the hopes of gaining company. He won't have to worry about that, though.
You know an MC has hit the bottom of the barrel when
he's taking tentacle rape...and this one--like so many others--is, apparently, an avatar of the author. Pathetic if the only way you can imagine yourself being with a woman is through the most degrading submission to one.