Rule 34 Dev - 00kaori00 animated_skeleton big_dom big_dom_small_sub bigger_dom bigger_dom_smaller_sub blue_blush blue_dick blue_eyes blue_penis blue_pupils blue_testicles blue_tongue blush blushing bone bottomless bottomless_male clothed clothing duo frottage frotting gay humanoid_robot male male/male male_only meta_request mettaton mettaton_ex penis penis_on_penis pink_glans robot robot_humanoid sans sans_blush sans_eye sans_glowing_eye sans_penis sitting skeleton small_sub small_sub_big_dom smaller_sub tears tongue tongue_out transparent_background undead undertale video_games yaoi|3534798912