[Tsumagomi Izumo] Yukemuri Sister (Aneniku Inmu) [MrBubbles]

A young boy slips into the open-air bath left over from his family's defunct inn for a late-night swim, only to be pulled into a steamy encounter with his busty older sister, whose soft lips and heavy breasts are just the beginning. She rides him until he's breathless, then eagerly offers herself from behind, moaning that it's too early to sleep as the two siblings lose themselves in each other under the crescent moon. Their blissful promise to 'do it a lot again tomorrow' gets a comedic punch when they finally notice the furry onlooker that has been soaking nearby the entire time.