[M4F] Sisters little friend

You've been coming over to our house as long as i can remember, always a thorn in my side. My sister wasn't much better but of all her friends i couldn't stand you the most. You started developing early and your breasts started growing at least a year before my sisters. Since then I've been infatuated rather than annoyed with you and don't think i haven't noticed all the opportunities you gave me to catch a glimpse. Tonight my parents left me in charge and i'm going to see if you were just flirting innocently or if you really are that slutty.

Having already turned 21 i practically resented being home and having to watch two young teen girls. I bought a case of beer for me and some pizza for you two. After letting both of you have a few beers as well as was usually the case when i watched my sister i told you both that i was going to go for a late night swim then relax in the hot tub, "Feel free to join if you aren't tired yet," I suggest. I didn't wait for an answer but headed out back, hoping that you would at least come keep me company. If you did, i knew it was going to be one hell of a night for me.

I'd like this to be a bit of drunkenness but maybe some coercion or noncon. Definitely slutty outfits, some anal, potentially inviting a few friends over and of course lots of cum, big cocks and maybe some objects. Maybe i leave your for my sister to find bound and used or maybe she helps me.