Watch the Bending 6ths: Study 2 online guitar lesson by Jason Loughlin from Country Guitar Survival Guide: Lead Edition
This study is dedicated to bending sixths as double stops. Bending sixths as a double stop can be challenging to do. Most of the time you have notes bending different distances. It's important to pay attention to the fingerings and which note leads the bend. Even though you should strive for perfection it's going to be hard to get it perfectly in tune. This takes a different kind of hand strength then you may be used to so don't expect it to happen the first day. It takes time to build new muscle. Of course, stop and take a break if you start to feel any pain in your hand. This technique works best on the top four strings. I tend to only use it on the 4th/2nd strings and the 3rd/1st strings. Nine times out of ten though I'm just using it on 3rd and 1st strings.