This is one of THE most adorable yaoi I have ever read. That says A LOT. It's not nearly as taboo as it sounds, it doesn't focus on the teacher/student thing which I normally definitely stay away from, but decided to try this anyway.
The teacher is adorable, makes me want to hug him and as for the student... So loving and dedicated!! When he cries it'll just make you freak out in the best way. (fujoshis can relate)
The art is magnificent, I love the different styles used for different expressions and actions, cute cartoony one, kid-looking one, and super cute adult looking one. Also, the age gap between Nagi (teacher) and Riku (student) is not even visibly noticeable. And of course, very very sexy and smutty when it needs to be.
I thoroughly enjoyed reading Oni Ni Hatsujou! 10/10. I want there to be a huge fandom for it like with Love Stage, because I feel like this really could go super far if it was more acknowledged!