Are her juices flowing when you guys are having sex? Does she get wet? If not, it could just be the fact that she's not lubricated.
If you're sticking ya peter in her when she's dry, then it's gonna hurt her. If you're using a condom, then you should be able to tell when she's becoming dry. Your condom will start to bunch up around the head and things should start feeling uncomfortable for you also.
If this is the case, I would recommend getting some lube. Some people use KY Jelly, because it's a house hold brand. It'll get the job done to a degree, but doesn't last very long (at least for me).
Others who know any better will tell you to go get Astroglide. I've personally never used it, but from what I've heard this stuff is the best on the market. It could probably be used in place of WD40.
I myself use Banana Boat Aloe Vera Gel. It comes in a clear bottle with a yellow top. Looks like green jelly. Not sure what your living status is, but you could keep this laying around and your parents wouldn't ask any questions. Personally, I just don't like having some girl over and pulling out a bottle of greasy lube that's wrapped in tissue to keep it from leaking all over everything in my drawer. Kills the moment.
If all else fails, you could always go with spit. Sounds gross and looks gross when I see guys in pornos do it, but it actually works. I personally wouldn't go spitting on some girls snatch just to get things moving, but I have spent a good amount of time giving oral to a girl that was known to be a little dry sometimes. Wasn't ever sure if it just got the juices flowing, or the spit from my mouth made it seem that way.
