I find that this bike doesn't turn over fast enough to get into too much trouble with engine braking, and dropping a gear or two will help get your speed down in a hurry. I always brake with the front first and add the rear "Gingerly". I find that you can lock the rear wheel on this bike going as slow as 25mph.
Things I learned the hard way!!! Don't shift into First in a turn! Don't shift into first in an attempt at engine braking. Both will result in a "highside" if you are not very quick or very lucky. I was neither