I fantasize about being a woman during masturbation.

I'm a 19 years old heterosexual cisgender male. I have always been attracted to women and never been attracted to men. I have always identified myself as a male and never wanted to be a female. I love being a male and I'm proud to be a male.

The problem is that sometimes during masturbation I fantasize about being a woman trapped under a man's body. What does that mean?

Look up autogynephilia and see if that fits...

Maybe you need to adventure out and have sex with a man while you play the female role. That way you can see if its something you really like or not. I put myself on the womans position everytime i watch porn or masterbate, i even have thoughts of transitioning into a full female, most of this is in me because i tried recieving anal sex and giving other men blowjobs and i loved it now thats pretty much all i ever thing about sex wise. You wont know if you really like it or not unless you try it. Good luck