coercion and compulsion both negate consent, which should be freely and enthusiastically given. you can't properly agree or say 'yes' to something you can't refuse or say 'no' to or when someone is badgering or harassing you into it. even if you're ignoring that suah non-consensually made juhyeok dependent on him and that is the whole (coerced) basis of their sexual relationship, consent can also be revoked in the middle of a previously agreed-to act, which juhyeok did when he first had penetrative sex with suah. suah ignored that juhyeok wanted to stop, therefore he is a rapist. he wasn't just being too rough (which is still reason enough to stop!), suah ignored juhyeok's "no".
Yes, did we forget that the main reason he even needs his cum is because Su ah marked him with his pheromone without Juhyeok knowing, even when he knew what it would cause to his body...su ah seemed very happy to know that Juhyeok needed his cum but wasn't very happy when he realised that it didn't translate to him falling in love with him
They were kids at the time (which is understandable) but he still continued doing it when they were adults without Juhyeok knowing just cus he was possessive, while also knowing that Juhyeok didn't like it and also explicitly told him to stop marking him (which without a doubt aggravated his condition)...also it's not as if Juhyeok was even willing to take his cum at the beginning but he still took it out of necessity, if we look back at it, Su ah very much enjoyed the fact that Juhyeok needed him (well...his cum atleast )

These bottoms with stand by their rapists no matter what bruhhh wdym you giving him a kiss after he raped you deadass the other day.