A desperate, needy sub, their cock trapped in a tight chastity cage, is presented with a tantalizing sight: a huge, veined dildo, wet and ready. The femdom mistress, unseen but authoritative, orders the sub to ride it, handsfree. The sub, whimpering and eager, grinds down, their tight asshole stretching to accommodate the immense girth. The dildo fills them completely, the sub's moans echoing as they fuck themselves, chasing their orgasm. The mistress watches, amused, as the sub's body convulses, their ass clenching, a handsfree cumshot painting their chest, a sissygasm achieved.