From my past experience.....
Every girl that I have sex with likes it more if you use your
tongue instead of your fingers. If you are using your fingers,
please do not put your four fingers in. Its painful for them. Start
with one finger at the coitus(top part of vaginal). When she is
wet, stick one finger into your vaginal. Go for the G-Spot(the top
part inside the vaginal, roughly 5cm into the hole. You will know
when you hit the G-spot because her reaction will change). You do
not have to use force. Rub the G-spot as tho you are applying
medication on your wound....meaning softly. If she hasn't reach
orgasm yet after 5 mins or so, go back to her coitus and do a left
right movement. Use a bit more force here and adjust your speed
according to her reaction. She will sooner or later come with
pleasure. I have an ex-partner telling me that she will take ages
to come but after I used this matter, she came within 15
mins.