Xbooru - 2010s 2018 2boys animated skeleton blue tongue bottom sans brother brother/brother brother and brother brothers clothed duo fontcest fontgalore grabbing face grey background hand incest male male only monster one eye closed out of frame pancakepants papyrus papyrus (undertale) papysans saliva saliva on finger saliva on tongue saliva trail sans sans (undertale) seme papyrus skeleton solid color background solo focus submissive tongue tongue out top papyrus uke sans undead undertale undertale (series) unseen character unseen male unseen male face upper body yaoi