Xbooru - 2010s 2018 2boys 2d 2d (artwork) anal anal penetration anal sex animated skeleton armwear black armwear black bodysuit black bottomwear black topwear blue blush blush blush lines bodily fluids bodysuit bottom sans bottomless bottomless male bottomwear brother brother/brother brother and brother brother penetrating brother brothers clothed clothing duo ectopenis ectoplasm fluids fontcest incest laying on back leg grab legs apart legs spread lying on back male male/male male focus male only male penetrating male pov mianpigui monster orange penis papyrus papyrus (undertale) papysans partially clothed penetrating pov penetration penetrator pov penis pillow pov sans sans (undertale) seme papyrus sex sitting skeleton solo focus tissue tissue paper top papyrus topwear uke sans undead undertale undertale (series) unseen male face used tissue video games visible breath wqw1201501125 yaoi