My sister had just left to go to high school so i thought I'll give myself a lot of time. I snuck under her door, and saw her room from a new view. Before i only went in her room a couple times when my sister carried me there, but the last time was 6 months ago. All i saw were piles of laundry that included panties, bras, shirts, pants, and a dildo or two. I then looked forward to see a dirty pair of bright green panties. They had a hole, and a stain from its long service, and was never cleaned once. Just the smell of her smelly, old, dirty panties turned me on. I dragged it into my room and spent the rest of the day having quality time with the pair of panties.
The green panties were really exciting, and the bad smell just made me more turned on. Everybody says my sister is gross even my family. Even though the smell is 100x worse or more at my size i simply ove her stink. Her pits, her feet, her ASS. Now i had a new plan. My sister sleeps naked so now that it is midnight i was going to see her sleep peacefully.
I slid under her door back into her room. As soon as i walked in i was hit by the smells of sweat, cum, and piss. I climbed her bed which was a mission all of its own. I finally got up to see her in all her glory. She was laying on her stomach so her big plump ass stuck out like a sore thumb. I walked onto her back right above her butt. Shit covered a lot of her butt, even a little above it. Pppppffffffffffftttttt. A loud sound shook the ground beneath me, and even sent huge ripples all through out her ass cheeks. The smell hit me like a heat wave, and made my nostrils burn. I took a deep breath through my nose and savored the sent. Sadly the smell of farts mostly got covered up by others in the pair of panties i found. Sis then started to rise lifting her head, holding herself up with her forearms. The arch created in her back from that sent me falling down it like a slide. At first i screamed, but silenced my self. I didn't want to be caught, and i realized i had landed between her cheeks. Sis then laid back down flat on her stomach. I wanted to save the wonders of her ass for another day.
I could smell the rachid smell of poop old and new covering her unwiped rear from probably months ago. I breathed it in, and almost went high on the fumes. I breathed and tried to control myself. I will wait till tomorrow till i go any further.