KissXSis - Season 1 Episode 12 One, Two, Threesome!

After Keita's graduation, Ako and Riko arrive to find they were too late to get the second, or any button, off of Keita's blazer. They decide to, against Keita's will, hold a draw for consolation prizes from Keita, with them, Mikazuki and Miharu as participants. Ako's hope backfires and ends up getting Keita's shirt collar, Mikazuki wins the opportunity for Keita to flip her skirt, though he is unaware she wasn't wearing any underwear. Riko wins a chance to kiss Keita in front of everyone, but is too embarrassed to do it. Miharu gets the remaining prize, to spend ten minutes in the equipment room alone with Keita to do anything. Keita simply uses the time to thank Miharu, but after a slip up, they end up in a compromising position, leading Ako and Riko to assume the worst. Later that night whilst Keita goes to sleep, Ako and Riko make a move on him, though this just gives Keita weird dreams.