Ingi is absolutley correct. Part of the way I increased confidence was by rubbing one out before having sex with her. I mean, not 2 minutes before sex...Usually an hour or maybe 2 hours before having sex. It works wonders....But no more than 2 hours
maybe masturbate more than once before being with her...Just try things...But don't tell her if you are uncomfortable...Wait until you are comfortable with her...To some girls it is very flattering to them when a guy cums fast...But eventually it will become annoying...So, eat well, exercise, take vitamins, do kegals (flexing your penis muscles...Try stopping urination mid stream, that is the muscle you want to flex), and have a positive attitude
attitude is everything