Rule 34 Dev - 1:1 1:1_aspect_ratio 2010s 2016 2boys 2d 2d_(artwork) animated_skeleton bigger_dom bigger_dom_smaller_sub bigger_male black_background black_hair blue_hoodie blue_jacket blue_tongue bottom_on_top bottom_sans clothed dark_background digital_media_(artwork) fel-fisk glowing hair hooded_jacket hoodie humanoid humanoid_robot jacket larger_male licking male male/male male_only mettasans mettaton mettaton_ex monster monster_boy one_eye_closed partially_clothed partially_nude pink_eyes pink_slippers pink_tongue robot robot_boy robot_humanoid sans sans_(undertale) seme_mettaton sinisk skeleton slippers small_sub small_sub_big_dom smaller_male smaller_sub smaller_sub_bigger_dom soul soul_sex sweat tongue tongue_out top_mettaton uke_sans undead undertale undertale_(series) video_game_character video_games yaoi|1015752