I know that this clip has been circulating more recently, but I just HAD to post it in case someone else hasn't seen this. It totally cracks me up!! I'm unable to embed the video, but here's the link!
This seems to be a recurring reaction to various different breeds of dogs when they get on the trampoline. I did a random search through YouTube of just dogs on trampolines and a variety of dogs that all had very similar reactions popped up. It was pretty funny! While me knee jerk reaction is "OMG, we need to get the dogs a trampoline (and I think I even texted this to Adam)!" With my luck, it would end very badly! Enjoy!