Damnit I didn't see where you had already taken it.
I will leave the rest of this mumbo below for reference for anyone else.
My 2 cents, and I've done it more times than I can count, is just sit back and relax. Make sure that you do all you can to avoid any confrontational types of circumstances, and you will absolutely enjoy yourself. I always new where I was, but I did get scared a few times. You just have to remember that there is no off switch as your friends father said. Be ready for a long ride, it will really depend on the cid though.
My bad experience was one of my earlier ones, I thought I had came down, because all of the enjoyable parts of the trip were over with, but I still couldn't think straight, it really wigged me out. But I was fine, it was some really strong cid and lasted about 12 hours. The last 4 had me worried.
If I knew then what I know now, I would have had some benzos around.