Uh, this is my take... and again let's put the 'rape is not cool' talk aside for now and just focus on the story, and seriously, let's not get confused there... this is rape.
It doesn't seem that Enzo's incapable of giving Rian pleasure, he's determined not to. He's working very hard not too. He even says "Do you really think I don't know where you'd like it", which means he had kept his promise that first night, making Rian come, just not the usual way. And again, not cool, but let's stick to the story.
Let's go back some chapters. He was definitely annoyed that Rian was going to do his job using the same methods, but while his threats were horrifying, flirting in his own way and with the intention of asserting dominance, they were provoking. Which means he knew Rian would sleep with his target, he just made sure to gain something out of it. Hint: he already had prepared the earing even before going to Rian's room.
So considering all that, what he's gaining? After all, he could be aggressive before and act worse, but he didn't. While having another hostage is a factor, it's also something he could use before. I think it's because he's a showman, who knows the importance of timing. And now he's changing Rian's anatomy with his participation, reluctant as it as, and he's making sure to stablish some sort of hierarchy between them. So it's not even about his own pleasure, while he's a sadist who's enjoying it anyway, obviously, he seemed more excited and... I don't know, crazy? that first night, while he looks totally in control here.
So, I really hope, fingers crossed, that he won't break his ribs. First because that would be very inconvenient for himself. He still needs to train Rian... I don't know, to match his mold? And second, he can bargain it with something else. I think that's something we should expect from him. He pushes Rian in a corner, then offers him some lesser evil, and since Rian doesn't really have a choice, it's Enzo's win either way. Wow, he's a demon for sure.
I think this is really interesting, not the story at this point, but the way authors react to how people take their stories. I think many of you have heard about Oda's reaction to fans calling One Piece sexist... and what does he do? Makes it more sexist. I'm not saying all authors reacts the same to negative comments, but I personally think the author has lost at least some of their motivation here. Even if the plot is still intact, it feels all over the place! That's true. I love this story. I love the characters. I love the art. And I hope people can keep their negative reactions in check, because it seems they're just killing the story.
It's fiction, and what really matters is not actually moral, good or bad, but being interesting or not. And unfortunately, I believe too many negative comments are killing its potential. So please people, back off, drop it if you hate it so much. You're ruining it for the other readers, and you're ruining it for the author, as unbelievable as it may sound! And don't say it's an illegal platform, the author doesn't care what we write here; that's not how the internet work.
Ok, I have an analysis for those who have been freaked out by this chapter, just like me. Now, after some overthinking, lol, I believe this might actually work! There are some points in this chapter, and I think I get the author’s plot somehow… I hope I’m right.
1. “Dumbass”, I wondered why it was made to sound so significant, but I remembered that Rian said that exact thing through the camera, when he first fooled Enzo. It’s not just Enzo’s possessiveness and libido that’s driving him; it’s also his petty revenge.
2. Then comes the second point. “I’m watching”, that goes back to the bar scene when Rian told him that if he wants a show, he should keep his eyes on him. He’s even holding a grudge over that, but it’s also like a promise between them: he’s paying attention.
3. The last point would be “If you did (know), you would’ve been extra careful not to let this body of yours go to waste.” Well, it’s not exactly the first time Enzo has called Rian a whore. There was that scene when Rian snaps at him that he’s not a whore to be paid for sex, and Enzo dismisses him by saying that ‘is there any difference’. Which obviously means, after the chip, Rian has gained Enzo’s attention/obsession, but not his respect. Enzo said mockingly that I should respect you as my partner, but the first part was that I should be able to trust you, which he already knows he can’t. So no, he doesn’t respect Rian… yet.
Now, my guesswork: Rian’s gonna earn his respect the second time he fools him, and it might not even happen that soon. I guess he might fool Enzo by playing along as if he has all the cards and can control every aspect of their relationship, and then he’s gonna take/use the info to make him bleed again, well, according to the weird definition of worthy gems in Enzo’s head. And that’s probably when we’re gonna have our separation arc, after Rian has gained Enzo’s respect and not just his obsession.