You probably feel very small in body size when you are changing in the male locker room, but not so good when its time to unzip your satisfaction gear and she is waiting.
Make Sure She’s aroused and her vagina is physically ready for you
You need to spend more time on foreplay than the average guy, and use extra lubrication. Even if she is a little bit wet. it will still hurt. Squeeze that tube of Play and don’t be stingy
Choose a position that doesnt allow deep penetration.
try side-by-side or one where she’s in control, like cow girl thus when she’s on top. when you first penetrate start by inserting a third of your penis, and get her to “bear down”. hold still until her vagina gets used to you,then you can go a little further.
Once you’re fully penetrated you can now very gently start going in and out , Deep and hard or fast thrusting is out unless she’s used to you and can cope