For people who are asking why Aaron is always on the edge with Yuujin... well it's cause Yuujin is hoe, the moment Aaron takes his eyes off of yuujin... yuujin is gonna hop on some other dick. And since their relationship is binded by contract technically Aaron can't say anything about whom yuujin actually wanna fuck. So Aaron's insecurities are basically manifesting into such rough sex and all those ass slapping. He wants yuujin to be sexually satisfied with himself so he won’t run off with others.
For people who are asking why Aaron is always on the edge with Yuujin... well it's cause Yuujin is hoe, the moment Aaron takes his eyes off of yuujin... yuujin is gonna hop on some other dick. And since their relationship is binded by contract technically Aaron can't say anything about whom yuujin actually wanna fuck. So Aaron's insecurities are basically manifesting into such rough sex and all those ass slapping. He wants yuujin to be sexually satisfied with himself so he won’t run off with others.