Young girls like to push the boundaries. They have just been given a freedom to explore their sexuality and they can't wait to go through trials and errors to see how far they can go with their new powers. I don't know if there is a lot you can do while she is in that phase and in that mode, especially if she's a type who subscribes to you only live once thus you should have these experiences. It's probably a phase she will grow out of in the future, how long that would take and whether your relationship will survive it is an entirely different question.
I don't think there is a lot you can do. You can have a talk with her and tell her how this is making you feel. But in the end if she continues and you are willing to tolerate it then that's the only thing you can do.
Don't cry, don't regret and don't blame
Weak find the whip, willing find freedom
Towards the sun, carry your name
In warm hands you are given
Ask the wind for the way
Uncertainty's gone, your path will unravel
Accept all as it is and do not blame
God or the Devil
~Born to Live - Mavrik~