Shinmai Maou no Testament: BURST - Toujou Basara no Shigoku Heiwa na Nichijou

新妹魔王の契約者 BURST 東城刃更の至極平和な日常

An OVA that was bundled with the seventh volume of the Shinmai Maou no Testament manga.

What’s the best way to celebrate a birthday? Well, to the succubus Maria, there’s only one thing to do—get Mio and Basara to hook up! Using the guise of Mio’s birthday, and a lust spell, she’s determined to have the perfect setup for a sexy celebration.

(Source: Funimation)