Most inelegant moment on horseback.
This, to my eternal shame, is me. On my lovely advanced dressage horse (who was facing the other way a few seconds earlier)!
I had something similar recently. Unfortunately I didn't get a photo.
I was hacking in a forest, we had stopped to graze and were on the buckle. The beast suddenly marched off under a nearby tree with a low hanging branch. I had to do a more extreme version of what you did, to stop him before I was swept off his back ?