first time

[cool-person-22]

Me and my gf tried having PIV sex for the first time, however, it was kind of hard for me to stay inside. She is tight down there, and she says that I'm the biggest she's had. I know it was just our first time, and it might get easier as we do it more, but I was wondering if you had any advice on this?

[Andy]

Hi there cool-person-22 and welcome to the boards!

So vaginas aren’t passive objects, they are muscles, which means they tense up and relax depending on what is going on, so the problem most likely isn’t with the size of any of yours organs. A lot of it has to do with how comfortable and aroused the person is, just like your shoulders get tense or your jaw tight when you are nervous. So the best advice we can get you is probably talking with your girlfriend about it, asking her how she is feeling about having this kind of sex, what might be helpful for her to relax, what she enjoys etc.
This article talks about this in more detail, gives a lot of practical tips how to deal with it as well as suggests other things that might be at play here (like lubrication for example): From OW! to WOW! Demystifying Painful Intercourse

Let us know if any questions arise during reading it or if there is anything else we can help you with!