Rule 34 Dev - 2010s 2017 2d 2d_(artwork) animated_skeleton artist_name blue_blush blue_tongue blush bottom_on_top bottom_sans completely_nude completely_nude_male cowgirl_position crypticcrows digital_media_(artwork) duo ectotongue elemental_creature elemental_humanoid fire_elemental glasses glasses_only gradient_background grillby grillsans humanoid male male/male male_only mari_keiyou_(artist) mk-doodles monster monster_boy nude nude_male orange_body penetration rectangular_eyewear rectangular_glasses sans sans_(undertale) seme_grillby sex skeleton top_grillby uke_sans undead undertale undertale_(series) video_game_character video_games yaoi|1030093