I posted an earlier video for the basic 1 arm kettlebell hip swing. As you all know, the 2 arm and 1 arm hip swings are considered the foundation of kettlebell training. Everyone should master both versions, as well as the kettlebell turkish getup, before attempting to incorporate other exercises and their variations.
However, for those who have mastered the basics, and who do not have very heavy kettlebells, here is a variation of the kettlebell swing you may wish to try.
The beauty of the double kettlebell swing is that it allows you to overload the hip and core musculature, even if you don't own heavier kettlebells. At the office, the heaviest kettlebell we have is 40kg or 88lbs. I would like to train with twice that weight, so the closest I can get right now is using (2) 32kg kettlebells, which translates into a total of 64 kg or 140.6 lbs.
The challenge is that as your kettlebell size increases, you must create a wider stance for them to pass under you hips. You must also be certain to rotate your wrist inward as you pass under your hips to make certain you do not hit the heavy kettlebell into your thigh. Believe me, that is a BAD idea! ROTATE THOSE WRISTS!