Xbooru - 2010s 2018 2boys 2d 2d (artwork) animated skeleton big dom big dom small sub bigger dom bigger dom smaller sub bottom sans bottomless brother brother/brother brother and brother brothers closed eyes crying digital media (artwork) duo ectoplasm fingering fingering another fingering partner fontcest gloves incest larger male male monochrome papyrus papyrus (undertale) papysans penetration pf-pro-fucker pf pro fucker sans sans (undertale) seme papyrus sex size difference skeleton small sub small sub big dom smaller sub smaller sub bigger dom solo focus top papyrus trembling uke sans undead undertale undertale (series) unseen male face video game character video games