
If you look at the way he tenderly held him, the way they both remained blushing, the way he came first, the way he didn't really try to actively push him away, the way he said slow down instead of stop, it's pretty clear that the both of them were feeling it or wanted it.
I think it was just too intense for him since it was the first time. Plus if you look again, he said all those things before he came which only further supports the possibility that it was just too intense for him since he never came from anal before, instead of it actually hurting a lot.

There will always be pain, it's anal, but the negative comments made it sound like the uke was just all in pain, which he wasn't. If he was indeed in great pain we would see him say stop, try to push him away, or say it hurts. But we didn't see any of those. All we see is him blushing, trying to hold on to him, saying to slow down instead of stopping, and even cumming first. It was just too intense for him as a first timer, which is he why he wants him to be slow but we all know that the seme has quite the high sex drive. And for him to finally have sex with his love, of course he'll get too greedy and rough. But overall, he wasn't even that "rough" to me.
Kinda pushy but still so hot...
The top could have been more attentive at the bottom's will but after re-reading it for the third time, I pay attention to the details in their positions and their hugs, and even if younseol is pushy He did ejaculate before the act because He knew he was thirsty about the uke to avoid hurting him.
I think they both wanted it but he tries is best to go slow at the beginning....
Even if I too, wanted that step to be tender, it is more real than fantasy, and I am so in love with that couple... I just wait for the smooth hugs after rought sex..