"Nurse Nasty," "Wicked Doctor," "The Prison Matron" … not the usual way to introduce yourself, but in the leather-clad world of sadomasochism, naughty is nice. And pain is pleasure. "I need stimulation and get a terrific high from playing rough," said Allena Gabosch, 52, a Seattle-based "bottom," meaning she's the one on the receiving end of spanking. The buxom, tattooed, alternative sex activist finds pain play very seductive but, "I still ask for Novocain at the dentist's office." While most couples don't need whips, paddles or ropes to get in the mood, a minority find sadomasochism, or S&M, erotic. They...