Originally Posted by David in PA
If a dog is meaning to hurt you no matter what, you will know it almost immediately. If he is lunging for your leg or body with teeth bared and is not backing off no matter what you do, use the spray--or whatever means are at your disposal. Again, you should only use the spray as a last resort.
Yes, learn to read dog's body language. If they are bouncing from side to side, they are playing. If they are coming straight with head low or head high, watch out!
A dog that is really set on taking a piece out of you is not going to be yapping all the way toward you. Most likely it will be silent. By the time it's lunging at you' it's too late for the spray, even if it's on your handlebar.