Inspired by poopisbrown.
Start by purchasing your favorite drink, whether it be beer, liquor, wine.whatever. Get nice and saucy.
Begin by fucking her the normal way. When she gets a little wet, take your cock out and use the tip to spread her wetness from her pussy to her ass. Stick your dick back in the pussy and fuck her till she gets even wetter. Take it out and rub the tip of you dick from her pussy to her ass again.
Being as this is her first time (so she says), make sure you are 6 strokes from cumming. Then accidentally slide your super wet cock into her ass, slowly!!. She will see its not as bad as she thought and will let you at it for a bit. (remember, 6 stroke max on a virgin ass!) You will bust your load in the poop shoot, everyone goes to bed happy.
Now, time two.
Begin fucking normal again. This time its in the back of her mind too. Play the nice guy roleact like you aint even thinking about going there this time. (it should help her relax a little).
Repeat pussy to ass dick slide to lube it up. Now you should be able to get away with 12 strokes in the ole fudge factory. (be sure of your ability to go 12 then nutno more!)
Now, you will want to dig your nails into her thighs and slam it in. Please resist! If you want the privilege to do it again, that is.
By time three if you did it right times one and two you're golden.