UMD-1010 Ruka Itoi, Rin Oka

My sister came to Tokyo for work with her colleague's boyfriend. Due to the inbound tourism boom, they couldn't find a hotel in the city center, so they ended up staying in my room... My sister, who was supposed to be sleeping next to me, moved to the living room where her boyfriend was sleeping. What?! They were having sex in my room?! I pretended to be asleep, but it was going on forever!! What?! How long is this going to last?! The next day I gave my sister a stern warning! When I asked her about it, she said her boyfriend is apparently a "super-sex addict." Sorry, but...