Rule 34 Dev - anal anal_sex anthro chastity_cage chastity_device collar duo equid equine female from_behind_position fucking_machine hi_res laboratory machine male mammal neysheli penetration piercing restrained restraints science_fiction scientific_experiment scientific_instrument sex sex_machine sex_toy sounding_rod stable standing_doggystyle urethral urethral_penetration vibrator vibrator_on_pussy wand_vibrator zebra|12467549400