He's glad that Dean is leaving the room for this. If Castiel is honest, he would prefer to be able to do this on his own, but to have one brother have to assist him is already bad enough. He's not sure if he could have taken the situation with both of them there.

As it is, he merely nods and slowly gets up on shaky legs, only barely wincing when he pulls some barely healed welts and shifts on the too big plug inside of himself. With Sam's patient coaxing he steps into one leg of both boxer and sweatpants, then the other, and breathes a little more easily once Sam has pulled them up.

He still feels naked. But he's covered, so that makes it easier to bear.

Castiel doesn't realize he let go of the collar and is loosely holding onto Sam's sleeve. As if he's temporarily finding safety elsewhere.