Microfic: The "Device" was really just a Fleshlight attached to a motorized arm that thrust forward and retracted. That, and a laptop propped on a shelf, web browser open to a GIF of a spiral. Noise-canceling headphones playing a simple mantra over a canned binaural beat.
But the power of hypnotic suggestion meant that, as he stood rigid in the living room, utterly paralyzed, unable to cum as the synthetic mouth milked his lubed-up cock, he was trapped inescapably in his deepest, darkest brainwashing fantasy.
The sex toy duct-taped to the motorized arm was a sophisticated biomechanical pleasure-control unit, its nanoscopic tendrils wound tightly 'round his sexual response. The reflexive twitch of his captive member was the only movement possible as it enslaved his nervous system.
The spiral GIF was a cunning hypnotic pattern jacked directly into his visual cortex—he could see nothing else as the subtle waves and pulses of light disrupted conscious thought and drained all trace of free will.
The voice in his ears—he could hear no other sound—had been installed at the center of his mind. His own thoughts were just noise, dim static ebbing away more and more as the tones and repetitive syllables reprogrammed him completely.
Aware of nothing but The Device that enthralled him, he could neither see the smile nor hear the aroused murmur of his Controller as they watched him descend into the dreamworld they'd so carefully designed.
His Controller was eager to touch and taste their compliant plaything, but that could come later... once he'd been reduced to the mindwiped drone that he so deeply desired to be.