"It's not as hot if you aren't into it," Ken observes with a slight huff, folding his arms over his chest. He's trying to make it sound like his only concern is that it's not as sexy, but...the entire point of the statement is that apparently Ken's sexual gratification hinges on Chikusa enjoying himself as much as he does. And no amount of attitude can really camouflage that as well as Ken might like.