So yesterday I was riding with a few friends (who don't bike very often) and of course I was the one to fall. I was only going 18 or so. There was a giant bump in the trail left by a pole that had been removed, and I just so happened to hit the bump while drinking and went head over bars, falling on the left side of my head and shoulder.
I was up immediately, and got away with scrapes on my elbows, left shoulder, right knee, a big patch on my back, a cut and scrape on my left wrist (with some swelling), a little swelling where I hit my head (although the helmet definitely helped me), and of course I managed to somehow hit my upper groin on something and now have a very uncomfortable bruise. Very Lucky!
So then I figured I could keep riding with my friends as they wanted to keep going, but when I got back on my bike I found the right shifter and break had twisted so as it was nearly paralleling the road instead of its normal perpendicular setting. Rode it over to my LBS and got it fixed up in 5 minutes or so.
Overall, probably one of the luckiest things to happen to me on my bike this month.

As an actual question though, does anyone have recommendations for drinking in very bumpy conditions? (yes I already knew the road was bumpy, stupid me). Is it just something that takes practice, or should I just avoid it all together?

Thanks!