Rule 34 Dev - 2010s 2018 2boys 2d 2d_(artwork) animated_skeleton ass ass_grab ass_squeeze bed bigger_male black_socks blue_tongue bottom_sans bottomwear butt_grab digital_media_(artwork) duo elemental_creature elemental_humanoid facing_another fire_elemental grabbing_ass grillby grillsans humanoid imminent_sex larger_male male male/male male_only mari_keiyou_(artist) mastery_position mk-doodles monster monster_boy on_bed orange_body pants partially_clothed pink_slippers sans sans_(undertale) sitting sitting_on_bed skeleton slippers smaller_male socks squeezing_ass tongue tongue_out topless topless_male traditional_art traditional_media traditional_media_(artwork) uke_sans undead undertale undertale_(series) video_game_character video_games yaoi|1030092