It’s Thursday night and I’ve just got home from work, it’s been a hell of a long day, I’m babysitting my youngest niece Mandy for my little sister, She is 14, her and my daughter are like best friends, I agreed to look after her as my sister wanted a break, she’s having issues with her oldest teenage daughter who’s 17 at the minute, mostly just sisterly arguments but she is a single mother so I can imagine how hard it for her sometimes.

Mandy is a girl who can be quite careless in terms of her self presentation and self awareness, for the past 3 days it’s been quite hard not to have any peaks at her knickers, for example if she’s watching tv with my daughter she’ll lie on her stomach on the floor and her legs will be slightly open or at the dinner table shell be slouching, I heard she’s starting wearing thongs lately but was unsure of this was true or not, I tend to grab a few pairs of her dirty knickers from the washing up basket when I visit my sister, not to often as I don’t want them realising some of these knickers missing everty time I visit them.

At dinner last night I purposely dropped a for fork so I had a reason to go under the table and had trouble seeing so I had to turn the light on my iPhone, as they were dark blue I couldn’t really tell much to my disappointment! I did how ever manage to see my daughters, (plain white knickers ... Mothers choice not mine!) she’s not at the the thong stage yet but hopefully soon her cousin might be an influence on her.

We ate dinner pretty late so I told them they could watch a movie in my daughters room and lights out straight after as I was pretty tired myself, Mandy asked me is it alright if she can borrow my phone charger tonight I said sure as long as I get it back by morning.

I turn the tv off and gradually fall asleep, I woke up a couple hours later realising I must have dosed off, I go the the girls room to grab my phone charger as I get closer I can hear something, at first I think it’s my Daughter Chloe snoring, I knock on the door and slowly open the door, what I see shocks me! I see my daughter asleep on the left side of the bed BUT on the rignt side I see Mandy Masturbating! She has her airpods in and can’t hear me, Chloes afraid of the dark so she keeps the night light on, I can’t believe what I’m seeing.

II see Mandys naked body, her legs fully wide open, I see her left hand holding her phone and her right hand frantically shoving 2 of her fingers in and out in and out, I can see the sweat dropping down from her forehead sliding down her body all the way down to our petite breasts.

The view of her her shaven pussy is absolutely breath taking, her face is completely soaked d it looks like she’s dumped her head in a bucket of water, I stand there and watching slowly masturbating as I savour this moment, where she’s ferociously masturbating the movement from shaking bed starts to wake Chloe, luckily she faced the other direction, this carries on for about another 5 mins, then it’s over she grabs the pillow behind and screams in to it, I see squirt after squirt shoot out of Mandys teenaged pussy, she breathing rapidly from the ferocious orgasm she just endured, I watch as she reaches over the side of the bed, grabs what appears to be a thong and drys her fully drenched pussy with it.

I run to the bathroom to confirm my suspicions. My sister was right she now wears thongs I held on pair to my nose, one pair to my cock and simultaneously sniff her thong and masturbate.

My cock erupts into her black thong, you can see the cum seeping through seems,

I throw the evidence in the washing machine and depart to bed, completely taken back to what I have witnessed