Not always lazy.
I used to hang out with a BDSM crowd and after smoking a little one night (I don't smoke it that often, so I have zero tolerance), got busy with a girl who was into biting and being bitten. It was pretty frenzied sex, and the biting didn't seem that bad. It didn't even hurt that much in the morning.
It was when my coworker asked me "What the hell happened to you?" that I actually went and looked in a mirror to see what the bites had done. She'd chewed through the skin in a couple of places and there was a 3 or 4 inch welt across the top of my shoulder, raised up about half an inch from swelling.
It didn't really hurt as much as it looked like it should have. More like a bruise
I've stayed away from girls who think they're vampires ever since though