Xbooru - 2boys 2males anal animated skeleton bigger male bigger penetrating bigger penetrating smaller blue body blue penis blue tongue bottom sans carrying chubby chubby male completely nude male cropped cropped image duo ectobody fire elemental from behind gay grillby grillby (undertale) grillsans larger male larger penetrating larger penetrating smaller legs lift male male/male male only male penetrated male penetrating male penetrating male orange body orange penis partially clothed male reverse suspended congress sans sans (undertale) seme grillby shirt up skeleton smaller male smaller penetrated socks text tongue tongue out top grillby uke sans undead undertale undertale (series) yaoi yore-donatsu