Well, he didn't force him but kinda blackmailed him. I think every character in this manga is fucked up seriously. (〜￣△￣)〜
Well, he did blackmail him, but it was also the uke's stupidity and self defeat evn before anything that allows those actions, which could be totally prevented, and in case of the older guy, now that he's successfully blackmailed him as he's wanted, he totally has the advantage here, he could evn abuse him or have rough BDSM sex with him, and the stupid uke will let him do all that without retaliating, but he didn't do those things, and was surprisingly gentle, or in any case, AT LEAST, better than the main lead seme here.
He was surprisingly so gentle with him and never forced him, I really shipped him and the uke, I was fantasizing about their relationship and how it would progress all in my head, so sad it didn't happen.