"If you don't keep up, you get punished," she warned her students at a recent class, which she oversaw with a nonstop string of insults and orders. "I don't want to hear any whimpering. You're here to suffer.

"I expect complete obedience, or I'll give you a good spanking," she said. "Do what I tell you to do. I don't care if it hurts..."

Clad in face masks, dog collars, rubber suits and other sartorial S&M paraphernalia, Mistress Victoria's students run through the exercise regimen, knowing any slacking off will bring her wrath down upon