Your step-mom is upset with you and she called you into her room to have a talk. She has to sit up on the bed with her. She's upset that you take her for granted and don't appreciate all she has done for you. After she grew you in her belly, and suffered as it grew large, and pushed you out of her vagina, stretching it out and damaging her body, you have the nerve to be a disrespectful step-son! She tells you that she's going to punish you for your own good, and makes you take off your clothes. She threatens you and you're terrified, and do as you're told. She is wearing a sexy outfit while she lubricates your butthole and you're so confused and you have strange feelings in your body. She inserts the hose of the aquarium pump and says it is perfectly safe, she's going to put air in your belly so you know what she suffered being pregnant with you. It slowly inflates and your step-mom is so good looking that with the pressure in your belly, you start to get a hard on. At the same time, your belly starts to cramp and you cry out in pain. Step-Mom tells you to stroke your dick, it will make it less painful, she's such a caring step-mommy. You do as she told and it distracts you from the air filling up your tummy. You get bigger and bigger and it's such a strange feeling, but arousing. She slaps your belly and even kicks it to simulate the kicks you gave her during pregnancy. You beg her to let you go and take out the air but she's determined that you'll look several months pregnant before she stops. You're so afraid you'll explode! But maybe you deserve it for being such a bad step-son. Finally she allows you to cum all over your big round balloon belly and takes the hose out after you promise to be good.