Ethnicity for sure.
Start off by saying do you happen to have any (whatever ethnicity you are) in you?
When she says no ask her simply if she would like to.
ZING!
You could always take her to the movies and bust out the popcorn trick
Step 1:
Purchase popcorn
Step 2:
Cut hole in bottom of popcorn container
Step 3:
Insert Penis in bottom/ hole of popcorn container
Step 4:
Offer some popcorn and tell her the stuff at the bottom is better
ZING!
No seriously it'll work and if it doesn't it was never meant to be.