Xbooru - 2020s 2023 2boys anal animated skeleton big dom big dom small sub bigger dom bigger dom smaller sub bigger male bigger penetrating bigger penetrating smaller blue hoodie blue jacket blush boots bottom sans bottomless bottomless male brother brother/brother brother and brother brother penetrating brother brothers duo ectopenis ectoplasm fontcest gloves hooded jacket hoodie incest jacket larger male larger penetrating male male/male male only male penetrating monster papyrus papyrus (undertale) papysans partially clothed partially clothed male penetration penis red boots red gloves red penis s2ames2 sans sans (undertale) seme papyrus sex sink size difference skeleton small sub small sub big dom smaller penetrated smaller sub smaller sub bigger dom socks sweat top papyrus uke sans undead undertale undertale (series) white background yaoi