Bad uncle

I'm a 44yo guy who has been separated for around three years, I have come to really enjoy masturbating and I like to have a bit of amphetamines when doing it as it makes me extremely **. I often use a site where I can ** off with other guys on cam.
My younger sister was going away for a long weekend and asked me to feed her dog and cat for her which I had no problem agreeing to. She left me the keys and I went over on the Friday evening to feed them for the first time. I had taken some amphetamines as I was planning on having a ** session when I returned home. I let myself in and got gave the animals their food and needed to use the toilet before I left.
My sister has two daughters Kelly 15yo and Emma who is twelve and they are both little cuties. As I walked from the bath room and walked past Kelly's room I spotted a pair of ** on the floor. I decided to check them out and to my delight they were dirty one's.
I gave them a sniff and I was in heaven, the scent of her ** was amazing. I stripped down and began playing with myself, I found another two pairs and they smelt just as good. I noticed some elastic hair ties on her drawer and decided to wrap them around my ** and ** as tight as I could, so much the veins were bulging and I was rock hard.
I played with myself sniffing one pair and stroking myself with another pair. I was really ** and a lot of pre ** was oozing from the head of my **.
Feeling naughty I rubbed my ** over her pillow case leaving a trail of pre ** along it. It wasn't long before I needed to ** and I blew a massive load inside the pillow case all over the pillow. I rubbed it into the pillow hoping it would dry before she returned. It turned me on thinking she would be sleeping with her head in My **.
I composed myself feeling guilty about what I had just done but thinking about it made me ** again. This time I went to Emma's room and in a basket in the corner I found two pairs of her unwashed ** and a little bra. Oh wow Emma's ** scent was sweet, ** I was turned on like never before. The second pair had some stains in them from her little ** and from her bottom, I couldn't help myself and began licking them, her ** stain was surprisingly a turn on and I was imagining licking her little ** hole. I could feel myself going to ** again and I blew my load over her pillow.
I took both their ** home with me and had a ** session on the cam site and the guy I was on with was impressed when I told him what I had done. The next evening I had another session in both the girls rooms but this time blowing into a fresh pair of ** from their drawers. By Sunday both their pillows were dry, you could see my stains and hopefully my sister thinks they both dribbled in their sleep.
Every time I visit now I try to sneak into their rooms to grab a pair, I have succeeded a few times. Now every time I look at Kelly and Emma I nearly get hard thinking I know what their ** smell like. I can't wait for them to plan another trip away and I will definitely be volunteering to feed the animals, I have a devious plan to ** over their toothbrushes. I don't know if I could bring myself to actually do it but I often think about it while jerking that they are brushing their teeth with uncles **.