Xbooru - 2010s 2017 2d 2d (artwork) 4boys animated skeleton blue blush blue tongue blush bottom sans bukkake clothed clothing cum cum in mouth cum on tongue digital media (artwork) ectotongue fangs finger in mouth fontcest gangbang gaster gaster (undertale) grillby grillby (undertale) grillsans hand implied incest lowest-of-dirt lowest of dirt male male/male male only monster multiple boys one eye closed orange cum orange penis papyrus papyrus (undertale) papysans penis red background sans sans (undertale) sanster seme gaster seme grillby seme papyrus sex skeleton solo focus tongue top gaster top grillby top papyrus tumblr uke sans undead undertale undertale (series) unseen character unseen male unseen male face upper body video game character video games yaoi