Yusuke's in a compromised place where he would agree to just about anything, so it's probably good that Luci isn't trying to get too wild. The playfulness is fun, a nice tease before things get too heavy, but her request is a tall order. No touching, when she's right there in front of him and he can still feel the hot sensation of her tongue on him.

It's a challenge. He likes a challenge, and he really likes being told what to do...in certain contexts, at least. Yusuke won't keep her waiting, but he will go slow, reaching up to unhook the buttons on her shirt at an agonizing pace.