First you must travel to a far away land that is riddled with dangers and quizzical challenges. You must pass through the towers that stretch the the heavens and descend into the labyrinth where you must retrieve a secret potion that will give you strength over the 7 seas...

Or you can just sit her down and say, I would really enjoy it if you were to play with yourself and let me lick your fingers clean. This isn't some mythical quest your going on. You just talk to her. Your a grown adult and if your old enough to be having sex you should be able to talk to her.

If she doesn't want to do it, you can talk to her and try to see why and what's wrong, but there are no sly "tricks" and "techniques" to MAKE her do it. All you can do is be supportive and allow it to occur

you might also bring a mutual game to the bed such that you will each mastUrbate in front of each other. Get creative and have fun with it

Wait till she is ready. Talk to her about sex like, her views and about you and her, generally-how your relationship is going is a start.