Dreamin' Wisteria

One day, Reto (protagonist of previous games by the dev, like Succubus in Wonderland) finds a painting of a mysterious storage room in Wonder Castle. Suddenly, the succubus depicted there begins to move, and he's sucked in. This succubus, Steria, will only let him escape the painting world if he can spend a week without ejaculating 5 or more times.