
So this chapter made me understand, or rather, have theories about Kenji. I agree with others in that Kenji is not a tsuandere. He is too much of a jackass. My three theories of Kenji are in that:
1) He is an incredibly guarded person (because of past traumas, etc.). Yoshito is very slowly starting to chip some of that wall away
2) There is a psychological theory called "love languages" in how couples communicate with one another. Kenji's way of showing affection is purely physical. Whereas Yoshito expresses his love more emotionally. They are complete opposites in how they show affection but this likely means they compliment each other well too. They are just slowly figuring out their styles.
3) Kenji likes being in control and being the dominant one in the relationship. I can definitely sense a S and M vibe in this relationship. Keniji = Sadist Yoshito = Masochist

I agree, especially with theory number one. As much as he pisses me off and I think that Yocchan should just move on to someone with a heart and a soul, I am under the impression that Kenji went through something that hurt him very, very deeply, and that he has still not recovered. Ryouichi is a jackass, and I think more is going to come out about their past and what he did to Kenji. I think there is probably a reason that he studies the martial arts so much, and is so unnerved and angry and hostile every time Yocchan has an effect on his heart. I have noticed with Yamamoto Sensei's works that when I really don't like something about one of her protagonists, she presents backstory eventually that makes me love that character and feel for them. She is very good with her characterization and motivation. That's my theory, anyway. I think his Sadist behavior is his version of testing the waters, though he is probably not consciously aware of it. He tries to push Yocchan away to guard his heart, but the more Yocchan stays anyway, the more Kenji feels secure, because even his ridiculous behavior hasn't driven him away, so he begins to feel like he might be able to trust him.

Oh, and the way he is so precise about boundaries sexually reminds me of someone who has been violated in some way. It's common for survivors of sexual assault to be very slow when it comes to expanding boundaries in a sexual relationship, and to test over and over to make sure their partner honors their boundaries. Before, when he said he didn't care about Yocchan's need to get off...that's actually a fair boundary to test, because so many men feel entitled to sexual gratification just because they have a boner, and/or they do something for someone. Kenji can't worry himself over someone else's gratification until he knows that person cares about his boundaries and bodily autonomy first.
But gah, he really is such an asshole to Yocchan. It's maddening!
I don't even smoke and I wanted a cigarette after those sex scenes. DAMN ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄