It's merely a role-play game that some users play. I confess that, when I was just a few days new to Second Life, I was tricked into accepting a bite and I found it a rather unpleasant experience. A message appeared on my screen telling me that I had lost ten percent of my humanity and, in my inexperience, I honestly thought that, if I were bitten nine more times, I would lose my account. This was, of course, untrue and I soon found a free garlic necklace that removed me from their "game." I would suggest that you search the marketplace and do likewise. Most importantly, there are no ill effects in being bitten.