You've always been an A+ student, particularly in chemistry, and you've finally found a way to make it worth your while. Your latest creation is a breast expansion formula. You're excited that this will get you money and popularity. Once added to water, it will cause the females cup size to grow. You've invited the popular girls from your school over for a pool party to test out your formula but you've forgotten about your stepmoms early swim. I enter your room covered in a towel asking if you've noticed anything with the family pool lately. You're too focused on getting ready for your pool party that you're oblivious to what I'm saying. Then it dawns on you what must've happened. You continue to try and play dumb. I demand to know whats going on. Suddenly I drop my towel and show you just how huge my boobs have gotten since my dip in the pool. I instinctively rub and bounce my boobs as I show them off. Even my ass has gotten curvier. You become erect as stepmommy plays with her big boobs. You reveal your dirty pool party plan to me. You didn't take into account the mammary glands jumpstarting the lactation process. My boobs are becoming full of milk, making them even bigger. step-Mommy wants you to use your clever mind to make her boobs even bigger than that though. You can't think of anything but step-mommy has an idea. I insist that you nurse from my boobs. Sucking means milk, and more milk means bigger boobs. I encourage you to keep sucking milk from my boobs. Then I take off my swimsuit and push you on the bed. step-Mommy rides you until we both cum. step-Mommy is still adamant about getting bigger boobs. It's time for you to cancel your pool party plans. Because step-mommy has something else in mind...