Where are you trying to lunge her? Don't give her the full 30' or however long your lunge is if she is acting poorly, but don't get her to close when she is blowing off steam. What happens when you lunge her after 5 - 10 minutes? She may just need to get the spice out! I am finding it is really hard to communicate lunging basics over a computer. Lunging takes a lot of patience and practice. Is there someone who could physically show you their lunging methods? If you lunge her in a round pen or riding ring you will have more control. Sometimes you just have to hang in there until they get their act together, but I don't want you to get run over or have her tripping over the lunge line if you aren't very familiar with lunging and she is acting like this. Try to get someone to show you their methods. This type of behavior is very common, and can result in a number of different scenarios.