I am your shy stepsister, and I just hit a sweaty gym session. Our stepmom asked me to always wear full coverage underwear for modesty, and I have been following obediently. To convince, I take off the pants and do some squats and show the outline of the big panties under the shorts. I pull the shorts to the side near my crotch to give you a peek and ultimately peel the shorts to confirm the granny undies. After you leave, I pull my fullbacks to the side and check if my string was perfectly hidden under the fullbacks and no one could see my secret. I rub my pussy lips and asshole over the tight floss and sniff my scent. Eventually you catch me, and I disclose the secret angrily. I wore a tight stringy panty, and they are completely buried deep inside my pussy and asshole. Soaked with my juices and stench. I flex my body and do some squats and talk about how the strings press tight which I love. You promise to not tell our stepmom if I allow you to sniff my string after my workout. I bend over and slowly peel down the granny undies exposing the string. I squeeze and spread my cheeks and pussy wide and command you to smell the panties. They are so stinky and gross. I talk about how they get wedged in between my lady parts and soak everything up. I show the front of the thong and ask you to sniff them. After teasing you to the core, I pull out the string from inside my lips and show you my dirty panties before getting dressed again.