A lot of things get to Yu, he's just has weird way of expressing them. And right now, he's also nervous and excited because Yosuke's allowing him to do this. And that speaks volumes to him.

Yu takes his time- his rubs shift between slow but hard and fast but light. Getting Yosuke completely washed over with pleasure is his goal, to get more of those sweet sounds from him. He could feel the other's heartbeat against his lips on the neck and he grazes his teeth across it.