Glimmering...Slapstick Christmas (OVA)

Some time after Rikka returns to the school, the gang has a Christmas party at Sanae's mansion. As usual, Rikka tries to take the opportunity to improve her relationship with Yūta, while Makoto tries to get closer to Kumin with no success and Shinka keeps arguing with Sanae. However, the situation gets even more hectic when Rikka and Sanae get drunk upon eating some liquor cake. After Rikka gets asleep, Yūta takes her home with him, but before returning to their apartment, they end up taking a special boat ride where they have some quality time until the rest of the gang also appears there, much to their surprise. The still drunk Sanae then causes a commotion about how Rikka keeps talking about Yūta, almost dropping Rikka from the boat, but Yūta manages to catch her in time, while Sanae falls over Shinka, kissing her up by accident. Finally back home, Yūta is visited by Rikka, wearing a black Santa dress to bid him Merry Christmas.