First, flick the clit with your tongue. Obviously thats the default move so alternate between licking the clit and licking the area around it so it doesn't get boring for either of you; like you're teasing her. Eventually introduce the finger to the g spot and do the same teasing method as with the clit. After a while go faster and cut the teasing and do this anon's method>>53421718
She'll be cumming in no time and you didn't even have to break a sweat.
For future sexy times try different tongue movements to keep it interesting.
And that's how you lick it.