My Sister-in-Law is Secretly a Succubus

You're married to Ava, a cheerful, caring, and dominant woman whose playful strictness and gentle control keep you constantly walking the line. But one day you find out her stepsister Alison is actually a corrupt succubus who seduces guys and drains their souls during sex. One night you watch Alison do her thing, but instead of exposing her, you make a dangerous deal. You'll keep her secret if she helps turn Ava into a naughty slut. Alison agrees, and from that moment, the real fun begins! Watch your wife slowly get corrupted and get maximum pleasure from it. What new fetishes will you introduce her to?