She took another and forwarded it on. She gasped, "Oh the girls love this one! They say you finally stopped looking down on me but rather up!" She looked back at you and smirked. "Seems about right. Staring right at my asshole if anything.."
She typed another message. "They're saying I should check your dick out - make sure you're not a perv for this kind of thing."
Before you could stop her she'd yanked the blanket off entirely. Your large veiny cock made a large tent in your white underwear - she could even see the tip had soaked through the fabric from the precum.
You felt horror tighten your chest before her cute giggles filled the air. "You're not supposed to like me silly! I'm your sister. Gosh did my big butt get you all confused?" She tried to push your cock down and you almost moaned - even the slightest bit of contact from her delicate hands on your cockhead drove you crazy. "Ugh gross! It won't go down." She covered you again with the blanket but didn't get up.
Instead her fingers slipped between the rim of her pants and her thighs. She slid her tight pants off. You stared up at her pink girly panties before she planted them on you as well. This time her bare smooth skin clapped against your cheeks and your nose was pressed into her crack. More photos - more laughing - more shame. Finally you wrestled her off you and jumped away.
She slowly walked around you to the door as you stuttered expletives and anger at her. She swayed her hips teasingly as she did - only serving to agitate you further as your hands cupped over your crotch in a bad attempt to hide your throbbing erection.
She paused at the door and turned around. "I won't tell anyone about this if you promise I get to sit on your face while I watch a movie later~"
You nodded shyly biting your lip so you didn't say anything and make it worse.
"Aaand you leave it to ME and not your girlfriend to train all of those perversions out of you. With more sitting!" She winked. She slid her hand up her legs to her hips then gave herself a shy slap on the butt.
You gazed at the empty space mind spinning. What did that wink mean?