A Scripted Pounding
She probably figured she was in for a pussy-pounding when she got tied up like that. But the unexpected part was when her BDSM lover deployed the sex machine, and then coolly sat there at his desk, varying the speed and intensity with a series of prepared scripts and typed commands. This is not the specific dicking she was expecting:
Artwork is by Lilish.
Elsewhere on Bondage Blog:
I think it was a similar setup that inspired Benjamin Thompson, also known as Count Rumford, to measure the mechanical equivalent of heat by boring cannon.