How do you BR?

So, I'm kind of in a weird situation. I just started playing WipEout again 3 weeks ago and I found out I could barrel roll which I wasn't aware of when I first played it. BRing came pretty naturally and I could do it consistently for about 2 weeks on all of the tracks. I got some pretty decent time trials... but for some reason I've completely fallen apart. One day I could do BRs every time I tried to do one, but the next day I couldn't do them anymore. Now I can only do a BR once in every 9 or 10 attempts... what happened?! It's extremely frustrating because it was so easy a week ago.

So... how exactly does one barrelroll? Keep in mind that I was able to do it before, so I know the button presses, but I just can't get the timing anymore for some reason. So, don't just tell me the button strokes. I'm interested in the timing. Maybe if someone could post a video of their hands when they do a barrelroll? =P

Any help would be appreciated... this is so frustrating >.<

You have to slow down. I've done the same thing, when you press L-R-L or R-L-R too fast, it doesn't register. Think to yourself "left-right-left" as you do it, that might help.
As to videos, go to youtube and search for leungbok/badtesterz videos. You can clearly hear his barrelroll tapping in the videos. TAP-TAP-TAP! Or just check out the Pulse speedlap videos thread here.

Thanks. The videos were especially helpful. They also showed me a lot of BRs I didn't know about. =D