Dean better get used to the idea of not being able to say anything out loud. That's going to be the case for quite awhile.

Dean being unable to do anything directly to satisfy himself was admittedly part of the allure of bending him over the desk. There's also where it was an effective means of showing dominance due to the way it permits him to restrain Dean for his own use and put him on display at the same time. Two birds with one stone.

Lucifer's hips snap forwards harder, pushing Dean to his limit in an attempt to give him that final push towards begging. The prospect of Dean doing so was exquisite. "Beg for me. You know you want to."