Xbooru - 2010s 2016 2boys anal animated skeleton big dom big dom small sub bigger dom bigger dom smaller sub bigger penetrating bigger penetrating smaller bottom sans brother/brother brother and brother brother penetrating brother brothers clothed clothing dirty talk duo eli-sin-g english text fontcest from behind position gloves grabbing from behind grabbing sheets gripping sheets hoodie incest kolesjoie larger penetrating larger penetrating smaller male male/male male only male penetrating monster onomatopoeia papyrus papyrus (undertale) papysans penetration penetration from behind sans sans (undertale) seme papyrus sex sex from behind skeleton small sub small sub big dom smaller penetrated smaller sub smaller sub bigger dom speech bubble text text bubble top-down bottom-up top papyrus uke sans undead undertale undertale (series) unseen male face yaoi