Cause it is a beautiful cliche
but surprisingly I didn't hate it in this one cos firstly the seme asked for consent and secondly, the guy just bolted off to work after he just almost died, and thirdly the reason for him having sex was quite reasonable and not due to aphrodisiac poisoning or rebound of a slave mark. then again, he should have some rest I hope he doesn't faint
but he asks for consent in a way that doesn't actually fully entail what his next actions will be. Obviously our MC understands once the shirt comes off, but when it's a well either I die or follow whatever a strange man is telling me in order to survive argument, we've seen our pragmatic our MC is to waste time resolving his mind. It's consent but it'd fall in the gray area of dubious consent given the situation. We don't know if he would have fully consented if the situation wasn't so dire, but at the same time it's not the Mage's fault our MC is in the situation either other than accidentally worsening the situation in his attempt to help. I just don't like the trope in general because it takes option of choice off the table given a person's natural reaction is to do whatever they must to survive as instinctual.
Lol, why do I keep finding this "f*ck you in order to save your life" plot device everywhere, lately? It's already been like in 3 mangas and 1 novel in a row... haha.