stepMOMMY is a taboo freak too

You have recently moved in with your stepMOMMY after going through a messy divorce and needing a place to call home for a while. Your stepMOMMY has no idea, but you've always had taboo fantasies about her and now, you have the perfect opportunity to masturbate yourself silly under her roof with a phone full of candid snaps of her. Using public places around the house to get caught with your hand down your trousers, your stepMOMMY hasn't really put two and two together.. YET, and today you purposely don't lock the bathroom door so she walks right in on you with your cock out in your hand, furiously masturbating with nothing to hide. She tells you that if you need to do that kinda thing you should either lock the door or go to your room in private, but you have a motive that she is about to discover.. you cover yourself up as she makes small talk about the divorce etc and goes to leave the room, which is when you accidentally on purpose flash your phone screen in her direction revealing a horror so shocking that she has to wrestle the mobile from you just to prove to herself she hasn't gone mad- a photo of her NAKED!! You are simply reveling in her discomfort.. she doesn't know what to say.. how to react.. a thing like this takes time to sink in, but you don't give her a second. Suddenly, you both hear your stepSISTER downstairs and your stepMOMMY rushes to lock you and her in the bathroom together, and shushes you- the last thing she wants is to be overheard having THIS type of conversation.. your stepMOMMY spends a short while gathering her thoughts and asking questions which only lead to more questions and you just admit it- that you have always had fantasies about her and you can't FUCKING HELP IT. She seems weirdly flattered but still suspicious and confused. She then notices your hard on pressing into your boxers and is lost for words.. all this while you can see her tiny tight yellow lace bra poking out from under her robe.. rock hard for your stepMOMMY, you sense she has something herself to admit to you.. and finally after trying to deny her own feelings, she crumbles and the truth comes flooding out... for the past 5 years she has had taboo fantasies about YOU.. what the fuck?! Is this even REAL?! You never imagined your prim and proper stepMOMMY would have perverted sexual thoughts like that.. and now that you know the feelings are mutual, you both don't see the point in fighting the inevitable.. the inevitability of horny, passionate taboo sex in the bathroom today...