Xbooru - 2010s 2015 2boys 2d 2d (artwork) animated skeleton bigger dom bigger dom smaller sub bigger male blue penis boots bottom sans calciumchan clothed digital media (artwork) drooling duo ectopenis footwear fully clothed high heel boots humanoid humanoid robot kneel larger male male male/male male only mettasans mettaton mettaton ex pee peeing peeing on another peeing on face penis pink boots pink high heel boots pissing pissing on face restrained robot robot humanoid sans sans (undertale) seme mettaton shoes skeleton small sub small sub big dom smaller male smaller sub smaller sub bigger dom third-party source tied up top mettaton uke sans undead undertale undertale (series) unseen male face urinating urinating male urination video games watersports white background yaoi