agree with Violet (for once) and several other posters: if it's easy to get DATY on the first date, she's doing it with everyone and it's not something you want. Work whatever form of magic you can with your fingers, then either politely ask or make it REALLY clear that that's where your kisses are headed.
If she politely declines the first time, she may never allow it.
If she politely declines in the second session, she probably won't allow it.
If she politely declines in the third session, you're almost definitely not getting anything.
If she politely declines in the fourth session - you're done with her, if that's what you're there for.
And yeah, it can take four.