I'm not psycho

John Waters's 50th summer in Provincetown

If you ask John Waters, Provincetown has become too dog-friendly.

"I'm more radical than PETA. I think dogs should be loose, running in packs downtown, jumping over the fence and biting everyone at tea dance -- not in some S/M relationship," Waters says. He produces a small plastic box embossed with the words barkstopper, ordered from an ad in the Nation…