Responses

i agree. tamaki needs someone that will push his buttons. and thats where shun comes in. a lot of people would think that no, shun will just make tamaki’s traumas worse. but that is not the case here. this is a psychological trauma where tamaki needs to overcome by doing the things he thought are, for the lack of better term, bad. and he needs to face and experience those thoughts head on, for him to overcome them and think that it’s okay to do those things. and he’s not harming anyone, nor his mother.
Shun is pushy since the beginning but you gotta admit Tamaki needs it. If Shun is not there I don't think Tamaki will want to face his trauma ever- he'll probably be a lot worse than now.
Also Shun did try to slow down. Hence, suggesting to quit the dating for a year thing.
And at the last chap(11), it is consensual. Tamaki gave in. He would have resisted otherwise or pushed Shun away. But they need a safe word.
I think some are repulse by Shun's actions because we are not used to a seme trying so hard to persuade the uke. We are used to a forceful seme pining down the uke without asking the uke's opinion and just going for it, and yet some find this more acceptable than Shun's???