i lwk think everyone here is wrong and the reason why he is so aggressive to not only dan but all his previous partners actually goes deeper. his whole life he was surrounded by violence/hurt. his dad who was abusive towards him, his mother leavinf him, and then being taken in by his former director only to be shown how to fight. he grew up taking his emotions out when fighting because that’s how he was trained. his whole life he has been near bad things, so it makes sense that he would be more on the aggressive side when love making. not justifying any actions he does in the manhwa, i am just explaining what i think
Since his first time, he'd been doing it just to distract himself, not for pleasure, right? That's why he never thought the need for foreplay, moreover to be lovey-dovey.
And i think people who are used to ons/whoring will understand to prepare themselves (they won't take the risk to get hurt, no?).
But it's different with kim dan since he knows nothing about it.

I really don't understand why he didn't do all this shit in the first place, I'm not talking eating him out, but asking if it hurts, or taking a min to stop to see if he okay if he notices discomfort during sex. like was it really that hard to ask these type of question when having an intimate moment with somebody. the fact that it took jjk Multiple chapters to have Consensual sex is throwing me off. but ig it was alr chapter.