When to use the clutch...

[Water Warrior 2]

You can brake in a turn if you use the rear brake only. You can use both in an emergency in a low speed turn but will like go down as the front end geometry will be upset in the turn as the forks compress and weight shifts.
As for higher speeds you can use both brakes to reduce your speed. The wheels act as gyroscopes and want to stay upright. The higher the speed the more stable you will be. There we go with the learning curve again !! I practiced high speed braking into a curve. I used a good piece of smooth curvy road (slightly downhill)with no dead critters or garbage on it. And definitely no tar snakes as they are scary under normal conditions in my opinion.