The way god does vibrato...
I managed to ignore this technique for the first 15 years I played guitar, man I wish I hadn't, it's really cool. Not I've got it down I use it as much or more than the standard 'pivot' vibrato.
If you are new to it I'd recommend starting with just 5 minutes a day for a few weeks to get let the muscles develop, starting in slowly and getting the technique solid. Get it into you muscle memory and then you'll just find yourself using it naturally. Might want to start on string 2 and only get into the thinnest string when you have mastered it on the others cos it is a lot harder!
You can clearly see Clapton using this technique on this video at 1:14 (thank Kris!)
If you need to ask a question about this lesson - there is a topic set up specifically to help you with this lesson. To help you find it easily you can click the following link and it will take you right the topic. You'll be able to see questions that other people had and ask your own questions! Hopefully one of the very helpful members of our community will be there to help you soon, I do go there and answer stuff too - but there are just too many questions for me to answer alone!