providers have their rules, so they should not be offended if hobbiysts have ruels to. Just say that it's your general rule and that it is not directed specially towards her. After that, it may well affect the sessoin but you have to chose for yourself what kind of risk you prefer: affecting the session or the possibility of getting an STD.

As far as knowing what to do "there", read the link to a thread that was just posted on the subject on the general discussion board, you'll find it quite informative. You can hurt her if you touch her clit too hard, or bite it or are rough, especially in the beginning when it's dry. So start by making it wet, be very gentle, and practise.

Good luck

M.