You have just discovered you have a fetish for lingerie and big tits after finding one of your Mommy's bras when she is out shopping. You've been secretly masturbating with her bras and lingerie for a while now but this time you are caught cock in hand by Mommy! At first she's shocked but then realises she needs to help her son with his fetish, explaining it's very normal to think about Mom when you're masturbating. It turns out that Mommy had been shopping for lingerie and she wants to show you all the new things she's bought, getting your opinion in return for her helping you get off. Mommy encourages you to stroke your cock for her and cum but one thing leads to another and it's not long before you are emptying your balls inside her while she rides you.