My Little Sister Is A Whore!

I guess technically I should say slut. She is a 17 year old who just stared her senior year of high school. I am a college senior at our states biggest college. Mom and dad have been pushing her to apply and fill out scholarship application. So last weekend she came up and spent the weekend with me.
I made the mistake of taking her to a big party after the football game. Of course I was trying to hook up so I wasn't keeping an eagle eye on my sister. She took advantage and had a few too many drinks. About 11pm I started looking around for her with no luck. Finally a girl I knew said she was upstairs. I pretty much knew what that meant. But she is 17 and old enough so it wasn't too big of a deal.
When I went upstairs the first thing I saw was a group of people standing at the entrance to a bedroom. I pushed my way to the front and got a surprise. I found my little sister. She was totally naked on the bed. On her hands and knees with two guys! She was sucking one guy as the other was fucking her from behind. There were several other guys gathered around the bed stroking their cocks waiting for their turn.
I had to walk in, tap the guy on his shoulder and make him pull his cock out of my sisters pussy! The other guy pulled away also. I led my naked sister through the crowd and out of the house. I couldn't find her clothes. Not to mention just how many guys might have fucked her???