Honestly, from what I've noticed, any 'rules' that she may have made up tend to dissolve after, safe, five minutes of head. There's a certain point at which the only thing a woman doesn't want you to do is stop. Seriously. As for not putting your tongue, ehem... inside of her, I've never heard of that. If your girl is the one that told you that she may just be self concious about her smell or flavor or what have you. A lot of women are self concious about being eaten out in general. S' a shame, but that's what we're here for: To break those walls down. It's a bloody public service!