The only acknowledgement Dean gives to the effort being made on his pants is to lift his hips slightly so he can have more access, while he continues sucking and biting at his collarbone. It's kind of freeing, being able to be a little rougher without worrying about hurting the person he's with, and he celebrates that freedom by finding one nipple and biting down on it harder than would be normally comfortable for someone else. Then he soothes his tongue over it, eyes flicking up to watch whatever is playing over Gabriel's face at the moment.