Your sister's shirt is removed, showing off her blue bra and she approaches you. Your own shirt is removed and then your pants. Your underwear comes off next and then your sister turns you over on the couch, grabbing your feet. She swallows them down, quickly getting them down her throat, and landing inside of her stomach. Olivia swallows even more, working her way up your legs and getting past your knees. She soon makes it to your crotch and teases your hard dick, before your hips slide between her lips.
Your stomach enters her mouth next and by this point she's really enjoying your taste. Olivia keeps going, getting up to your chest. Your shoulders slide in between her lips next and by this point, you notice the bulge you are making in her belly and are aroused by the sight. Olivia slurps more of you up, getting your head inside of her mouth. Soon, her teeth close and the rest of you is quickly headed for her gut. You curl up inside and relax.
"Happy birthday, Ben." she said, patting her belly.