WARNING! It’s not gonna be that warm as you think. It can make a 10 degrees difference which is still pretty good. Make sure you block out air and try keeping the dust away from you as it can irritate your lungs. Later on you could use leafs, moss inside
MORE TIPS IN THE COMMENTS
Quickly edited video to demonstrate :-).
I was at the forest and thought of this suddenly 🙂.
Don’t make it too big, more tight and as much insulation, covering!