You walk behind Jessica and stick the tip of your cock between her asscheeks. "Oh boy," you say, "this'll be fun." You thrust forward, recieving a cry of joy from Jessica. You keep thrusting, harder and harder until she's basically begging for you to cum. After a few minutes of anal pounding, you shove your cock as far into her as you can. She makes one loud, lusty gasp right before you finish.
You blow your load inside her, instantly filling up her stomach. She moans in pleasure as you keep cumming, overfilling her. You keep cumming, forcing more and more cum into her now extending belly. She rubs the new curve, all the while moaning from lust, jyo, and a tiny bit of pain.
Jessica's stomach continues to grow, soon reaching the size of a three month old pregnancy. her belly still grows, rounding out and stretching, soon making her look like she's about to deliver. She still grows, her belly soon reachnig the size of an over-filled beachball. She begs you to stop, but she also begs for you to keep going.