Guys love it when they are challenged.
If you make it too easy they tend to lose interest.
Let him take the initiative instead.
Build up chemistry and fun and stay on the light, innocent and casual flirting territory.
If you had a great time and want to see him again, when you are about to go, turn to him, give him your number, smile, look at him straight in the eyes and say: “Call me”
As soon as you take that step, you enter into the seduction zone.
It is a significant shift and opens the door to a whole new world of emotions between the two of you.
If for any reason, this strategy does not work, then sure, get his email or phone number.