lets try for one serious feckin answer... jesh what a sad bunch.
have a few drinks first, it will loosed both of u up and get rid of any inhibitions.
then take it slowly, spend a good half hour on each other just getting aroused, then when its right you will have no problems.
you may not have been able to penetrate the 2nd time if she was too dry, so mak sure shes really aroused, or try some sort of baby oil to help with lubrication, shes gonna be nervous as well, so just relax and let nature take over...