Hybrid x Heart Magias Academy Ataraxia

Hida Kizuna possesses the HHG (Heart Hybrid Gear) ability, but it is not strong enough to make him particularly important. His older sister calls him to transfer to a strategic defense school, where many of the students (many of which are large-breasted girls) use their HHG abilities to fight invaders from another world while wearing extremely skimpy pilot outfits. Kizuna's fighting ability doesn't measure up, but his sister has another plan; getting the girls to have erotic experiences with Kizuna, so that it will allow them to replenish their energy or power-up. It looks like his new school life is going to be full of embarrassment! (Source: MangaHelpers)

Simoun

In the peaceful theocracy of Simulicram, everyone is born female. At age 19, each maiden undergoes a special ceremony where she chooses her sex. However, only Pairs of maiden priestesses can synchronize with the ancient flying ships known as Simoun needed to defend Simulicram. These Pairs refrain from undergoing the ceremony as long as they wish to keep piloting their Simoun. Aer is recruited to be a Simoun pilot after a terrifying attack by an enemy nation decimates the squadron known as Chor Tempest. To earn her wings she needs to find her way into the heart of Neviril, Regina of Chor Tempest. But Neviril's heart still belongs to her previous Pair, lost in the battle when she attempted a forbidden Simoun maneuver. (Source: Media Blasters)