This might not seem intuitive at first, but give it a try!

We know that applying the rear brake while doing a wheelie or manual will usually result in a very quick "shut down" or dropping the front wheel back to the ground.

On the other hand, correctly applying the rear brake, with a lot of modulation ( and practice ) can help you to maintain and correct your balance while riding on the rear wheel.?

This is a great exercise for wheelies, but also to improve your braking ability.