I'll clarify something quickly: when he said, "Do you really think I don't know where you'd like it," he was referring to Uno's d*ck. He was holding it while saying that, and he's fully aware that Rian's only source of pleasure was through stroking and giving attention to his d*ck. However, Rian couldn't feel anything at that moment because he was cock-ringed, and of course Enzo knew that too, since his intention was exactly to prevent him from using his d*ck again and thus having s*x.
So, he prioritized his own pleasure first, and only after that did he attempt to give Rian some relief by stroking him. Unfortunately, at that stage, Rian was unable to respond anymore due to the pain he had endured.
So yeah, it's obvious Enzo wants to "punish" Adrian rather than pleasure him. It doesn't change the fact that a second chapter focusing only on torture and s*xual violence, when it's been like this since the comeback, is at this point becoming repetitive rather than impactful. When every chapter relies on the same cycle of grape, suffering and humiliation, it stops adding anything new to the story or the characters (doesn't necessarily deepen them or advance the story in a meaningful way, it just reinforces information the audience already understands) and instead feels like shock value being stretched out for far too long.
And after a while, constant gruesomeness stops feeling shocking or meaningful and instead becomes exhausting.
Also, another point: if every sexual encounter we're shown is framed around control, humiliation, or punishment, then there's no actual basis for claiming that Enzo is good at sex either.
If anything, whether he's actually good at pleasing a partner is still there to be proven, because the story has yet to show much evidence of it.
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.