Accidentally got piped by my bestfriend

I took a trip to my hometown in SoCal over the weekend to visit some friends. I ended up staying the night at one of my close friends' house, and he actually invited some girls over, some of which I knew from college and some of which I had never met before. Everything was going well, but then things took a turn for the worst. One of the girls said to my friend "if you hookup with (my name) then I'll suck your dick". Initially everyone just laughed, but she kept saying she was serious. I could see in my friends' eye that he was actually willing to fuck me to get with this girl, but I was having no part in it. He actually came over and grabbed my arm, half joking but half serious, as all the girls watched and laughed. I pushed him away but then he literally grabbed me, ripped off the Chinos I bought from banana republic and then banged me. Like he straight up piped me from behind in front of all the girls, just so that one chick would suck him off. He was too big for me to fend off and it just happened so quickly. I immediately drove home and now I'm contemplating what I should do. Also I forgot to mention but one of the girls who is there is good friends with my sister and I know she's gonna tell her what happened, and then my sister will surely tell my parents. Advice??