Rule 34 Dev - 2010s 2017 2boys animated_skeleton bed bedroom blanket bottom_sans brother brother/brother brother_and_brother brothers bulge clothed clothing comic comic_page comic_panel dry_humping duo erection erection_under_clothes fontcest glowing glowing_genitalia humping incest indoors intraspecies laying_on_bed lying_on_bed male male/male male_only monochrome monster monster_boy on_bed papyrus papyrus_(undertale) papysans partially_colored sans sans_(undertale) seme_papyrus sequence sequential sibling_incest siblings skeleton supermuuh top_papyrus uke_sans undead under_blanket undertale undertale_(series) unseen_male_face yaoi|1030640