Might he have a Urinary Tract Infection? Maybe time for a vet trip. Is he neutered? (I forget) Some intact males need to mark their territory.

Miss Hoppy, being a typical bunny, has a "big shed" twice a year, in the "sping" and the "fall" - otherwise she just sheds a little, but at those times, you'd swear more fur comes of than a whole rabbit holds! I pet her outside then, so the wind can take it away, and I am sure all the baby birdies in my neighborhood grow up with the softest bunny-fuzz-lined nests!