Xbooru - 2010s 2016 2boys 2d 2d (artwork) animated skeleton arms behind back artist name beoteono black tentacles blue blush blue penis blush bodily fluids bottom sans buttercupsticks clothed clothing cussing dominant dominant male drooling duo ectopenis feet out of frame fluids gaster gaster (undertale) grabbing another's chin grabbing chin grey background hand under chin hands behind back male male/male male focus male only maledom malesub monster one eye closed partially colored penis precum profanity sans sans (undertale) sanster seme gaster simple background skeleton soul soul sex submissive submissive male swearing tentacle tentacle on male tentacles tentacles around legs tentacles on male text top gaster uke sans undead undertale undertale (series) video games yaoi