His face flushes an even brighter red now. It's totally embarrassing to think about, but at the same time. He's got that image of himself and Yu doing something dirty in his head, and it would be a lie to say that that flustered him a bit in a different sense too.

"Stop that, dammit! That's making me all excited." He looks angry, and part of him is- but the other part would just prefer to shut him up by sealing the sound away with a kiss. Which he might end up doing if Yu pushes it.