I've only been back from boarding school for a couple of weeks, and I've caught you going through my dirty laundry and sniffing my sweaty socks - gross! What's even worse is that after I caught you the first time, I installed a camera in my room, so that I'd know if you did it again, and not only have you been SNIFFING my socks but you've been jerking off wit them!!! That's SO disgusting - I'm your step-s1ster for heaven's sake!
So, I've been thinking of how we can deal with this and I've decided that for the whole summer, you can be my foot slave. If I want a foot rub, you do it, if I want you to lick the soles of my shoes, you do it, understand?
Oh, and one more thing - if you refuse, I'll send the footage of you wanking over my socks to EVERYONE