Kämpfer

Kämpfer is a 12-episode Japanese anime series by Nomad, based on the series of light novels written by Toshihiko Tsukiji. The series follows a boy named Natsuru Senō, who is chosen to participate in the Kämpfer battles, giving him the ability to transform into a girl.

His Midsummer: Tropical Cyclone of Romance (Episode 9)
Near the end of the episode Kaede hypnotize Natsuru and ask him to come see the fireworks with her alone.

Her Trap: A Summer Experience (Episode 10)
Natsuru finds himself next to Kaede, who hypnotise him to making Shizuku his. Kaede then disappears when Natsuru, who can't remember anything, is confronted by Akane, Shizuku and Mikoto. They return to the hotel where Kaede doesn't appear to recall either. Afterwards, they all go to the baths, where Natsuru's hypnotism kicks in and he goes over to Shizuku's room to make a move. Shizuku realise that something is wrong with him and knock him out.

Choose: A Song of Joy (Episode 11)
Sakura brainwash Natsuru again, this time to make him fight against his allies.

Temptation: Stealing Ahead (Episode 13)
Mikoto is hypnotised by the Bakahatsu Penguin and used by Kaede to fight against Natsuru and his friends