Kakushite! Makina-san!!

Eita Akutsu is a loner and an introverted mecha otaku. One night, the cheerful and popular gyaru, Makina Agatsuma, suddenly appears in his apartment. But something seems off about her. When she abruptly strips in front of him… what he sees is not a human body, but a mechanical one! Makina is an AI robot designed for intimacy, yet she's been restricted from accessing any adult-related information. Eita, on the other hand, is a pure-hearted virgin who is extremely awkward with anything lewd. Thus begins their top-secret cohabitation, where no one must find out her true nature! (Source: OceanVeil)