Rule 34 Dev - anal anal_sex android animated_skeleton blush bone clothed clothing duo hair heart hotlegmeme humanoid machine male mettaton mettaton_ex monster multi_arm multi_eye multi_limb open_mouth pappyrus papyrus penetration penis robot sex simple_background skeleton teeth undead underfell underfell_metaton underfell_papyrus undertale undertale_fanfiction video_games white_background yaoi|2204309816