Watching badass blood-suckers cavort on Buffy the Vampire Slayer has made heaven knows how many viewers wish that they could let their inner creatures of the night have their day. But it's not all hemoglobin and hair gel for the undead, reveals Mercedes McNab, who plays Spike's dingbat ex-ghoulfriend Harmony.

In particular, the actress tells TV Guide Online, it's the false teeth that pose a real challenge. "When they fit correctly, it's quite easy for me to talk with my fangs in. As a child, I always had retainers and braces behind my teeth, so I'm kind of used to having weird things in my mouth.

"But after I got my wisdom teeth pulled, my teeth were always moving," she continues, "so every time I'd do an episode, I couldn't get [the faux choppers] in, or I'd put them in and they'd break halfway through a scene and I'd be prancing around, trying not to step on them. You'll notice that sometimes I have a lisp, too."

However, McNab never gives her bosses any lip regarding her difficulties. She prefers to put up her dukes. "I definitely get riled up doing fight scenes," she admits with a laugh. "I love all the kicking and the beating up. It's fun to get out that aggression."

Of course, losing her teeth would still be a concern if she were to take the advice of the series' fisticuff choreographers. "They always tell me that I missed my calling and I should have been a stuntwoman," she reveals. "I'm like, 'Yeah, thank God it's just fake fighting, or I'd get killed!'"