Xbooru - 2010s 2016 2boys anal animated skeleton blue blush blue penis blue tongue blush bottom sans bottomless bottomless male brother/brother brother penetrating brother brothers duo ectopenis ectotongue fontcest gay gloves incest male male/male male only male penetrated male penetrating male penetrating male monochrome monster orange blush orange penis orange tongue papyrus papyrus (undertale) papysans partially colored penetration penis sans sans (undertale) seme papyrus sex shirt only skeleton skullysins table sex thrusting tongue tongue out top papyrus uke sans undead undertale undertale (series) yaoi