I also read that if it's attacking, give up your forearm and then fall or roll onto your back, wrap your legs around the dogs body, push out with your arm if you can and squeeze for all you're worth with your legs. They claim you can squeeze the air out of them this way and in some cases, snap the spine.
no clue if it works
I'm always looking for ways to deal with dogs, on my bike i get the shit scared out of me by dogs out on country roads at least 3 or 4 times a year
I have a feeling that if was ME getting attacked, it wouldn't work out this way:
http://www.bikeforums.net/showthread.php?t=113660