@Noyoki Yes, we are reading the same story: in the previuos chapter the MC asked Monster Mugo to refrain from pressing, and at the very beginning of this one also said he could not breath well. From my point of view this is totally unwelcome. It's a trigger for me, but this doesn't mean that has to be unpleasant for other readers, so simply enjoy it, if it's good for you.
You are my happy ending Hail the holy banana! Serious note - If you put a placeholder, please remember to upload the correct chapter
1.) He couldn't breathe because the train car was packed and Monster Mugo was pressing into him as a result. It was more a combination of "breathless" and "crushed" but not because it was Monster Mugo doing it. Not sexual harassment.
2.) He specifically said "NOT HERE" and that he'd "take care of it" elsewhere. AND his "not here" was talking about the fact that Monster Mugo was pressing directly on his a****** like he was gonna penetrate him on the train, NOT because he wasn't willing. Not sexual harassment.
3.) Monster Mugo backed off THE MOMENT HE WAS TOLD TO. If this actually was sexual harassment, he would've kept it up, because those types of people don't care when their targets tell them to stop.
Sexual harassment may be a trigger for you, but this isn't sexual harassment. Not even remotely, and I'm really confused as to how you're viewing it as such.