Xbooru - 2010s 2017 2boys anal animated skeleton bigger dom bigger dom smaller sub bigger male bigger penetrating bigger penetrating smaller blue blush blue hoodie blue jacket blue tongue blush bottom sans bottomless crying crying with eyes open duo ectoplasm fire elemental gigandam glasses grillby grillby (undertale) grillsans hooded jacket hoodie larger male larger penetrating larger penetrating smaller male male/male male only one eye closed orange body pants penetration pixiv id 780096 rectangular eyewear rectangular glasses sans sans (undertale) seme grillby sex shirt up sitting size difference skeleton small sub small sub big dom smaller penetrated smaller sub smaller sub bigger dom sweat tears tongue tongue out top grillby topless topless male uke sans undead undertale undertale (series) video games