Make sure that when you're rubbing your hands together you're really focusing on the feeling of it, feel the friction and all, and try to make sure that feeling overwhelms anything that might come from your actual body as you're waking up. Maybe try looking closely at the ground too, noticing every detail there is of it. Basically, from my experience the more senses you've got telling you stuff from the dream and the more strongly you're paying attention to them the better your chances of staying in the dream. Whenever I'm not in a bloody dry-spell like now, I can often pull myself back from pretty much being fully awake just doing that. Just keep imagining the feeling off it all, while doing your best to keep completely still and ignore any actual feelings from your body

And if it still doesn't work for you, maybe try spinning instead of hand-rubbing. It's never worked for me, but for some people it seems to works a lot better