I have such a hard time looking at their sex scenes, is it just me?

I wouldn't say a hard time looking, it's not badly drawn but hmm they feel not as smutty as other pieces. Their expressions are quite bland too. I think they are settling for a more realistic approach which is why you might be struggling.

I figured it out, I think that Luca's dialogue is not very sexy and kind of a turn off

I think Luca is doing that on purpose because Dojin keeps putting up a wall. So his dialogue seems a bit distant. I think when Dojin opens up a bit more Luca will be more affectionate. We just have to wait and see.