How do you get a girl to let you lick her pussy?

JUST ASK! And don't be afraid of rejection. If you ask 10 hot women then 5 will look at you like you're crazy, 3 will laugh and tell all of their friends and make you look like a fool and 2 will say yes and let you. Maybe it is best to ask girls that you have some rapport with and trust will preserve your dignity if they're not into it. All girls will wanna say "yes" so its just a question of you making them feel sexy and gaining their trust that you will do it discreetly and that there won't be any negative social ramifications