
There are a lot of different opinions on this so I'd like to share mine.
I am not trying to justify Shii's actions, because forcing tamaki was not appropritate at all. On the other hand, hes a 14 year old boy who realized that his crush is planning on not looking at him that way at all. Which made him desperate cuz u knw. Hes been crushing for so long! And then that happened. He masturbated to that tamaki and in post nut clarity realized 1. Tamaki DOES NOT want him in a sexual way (I dont think shii knows fully how deep tamakis trauma goes. He just thinks tamaki cant do it with girls cuz he heard his mom once) and 2. He REALLY wants to do it with tamaki. Again, hes freaking 14-15. So i think he tried finding the next best thing, which in his eyes, would make him 'less dangerous' to tamaki, and not hurt tamaki again. That solution was to get rid of his excessive sexul desire for tamaki but doing it with a fake tamaki as he says. He did it and from what I understood, while he felt physically good, mentally he kept imagining tamaki and when it wasnt, there was this feeling of emptiness. So he apologized to his fake tamaki for using him. The advice part was mostly from the side of fake tamaki (yea i forgot his name) which may or may not help idk yet.
Its like...it was a twisted concept but the author made it sweet. Soo cute!!