Her Electric Strapon

Mistress Sidonia is using her large, solid metal strapon to fuck her suspended slave. She has evilly electrified it with her E-Stim box, so it makes his ass contract and quiver with each thrust of the solid phallus. Mistress exerts full control, moving him around at her whim as she fucks him deep and hard before leaving him with the dildo inserted and locked into place, the electrics still active.