After a few times if you and her click (almost any lady) there will be a connection where you can try to initiate the LFK or DFK. If at first during that time (between 4 to 6 visits of good conversation and mutual respect), and she looks at you and not look off somewhere in the room, you can initiate. If she pulls away, then either she does not want to go next level with you, or best case rejection scenario would be Tim Hortons Roll up the rim "Sorry, play again"
This opens up for you to visit a few more times of visits before rolling up the rim again. If you could convince her and proof that your experience would be enchanced with some LFK and DFK, then maybe she might since you might finish faster.
You also must prepare first for the visit too by brushing, flossing and mouthwash prior to visit and did not indulge in a meal packed with garlic and onions. YMMV but from my experience in the past, it can happen. But are you willing to invest about 8 or so visits?