the slap of disgust....

Lord that part of him really pisses me off what a jerk

That's what I thought at first to but after rereading it I noticed Yeonwu was getting ready to rub Taewan's dick with his foot. I think it was more or less a, "Don't touch me. I'm in control here" response. I think Taewan just wanted to torture him a bit more. If you notice he follows the comment. With, "Maybe I'll put it in if your good."