He can be assertive--this is just all new to him. But he likes it, having a girlfriend. He likes kissing her too, which is why he wanted to do that to say thank you.

Of course, with her suggestion, his blush deepens.

"Uh...that...I...huh?" So very eloquent there, as his brain is going in many different directions. One direction is very aware that anyone could walk in--she'd JUST POINTED THAT OUT. Another part is aware that she is very pretty girl who likes him. Who he likes back and wants to keep kissing. A third part of him wants to check out the ARMS band, and is curious.