Art is good, that much is true but this is basically a story about a guy raping his 'friend' while the other one sleeps. And no, the fact that the guy (uke) feels aroused remembering some of it DOES NOT EQUAL to consent... The same is when some people have a kink for "being raped" does not mean they want to get raped and should not be viewed as such, a imagination is one thing a reality is another.
It's a shame that the author decided to go this path because I think their art style is very pretty
edit:
If I could just forget the whole volume 1 the second vol seams much better
Yamashii Koi no Hajimekata