Tsumugi no Hanayome

Aoi and Yamabuki are childhood friends. Aoi is the quiet introverted one, while Yamabuki is the loud extroverted one. One night Yamabuki takes Aoi out to a shrine where Aoi gets possessed by a haunted relic spirit that causes the possessed to grow a penis. Together Yamabuki and Aoi go from childhood friends to lovers as they overcome adversity and find true love with one another.