Is my penis too heavy when erect?

I seem to have always had this problem ever since puberty, which makes for no fun when trying have penetrative intercourse with a partner. The problem is that my penis is too heavy when I have an erection so it bends right at the base of the shaft and this is sometimes painful and pinching. My boyfriend's penis is nearly as long and significantly thicker, but his sticks straight out as if he has it braced with a rod while my penis is struggling under its own weight. Is there some sort of exercise I can do to increase the hardness of my penis, specifically the corpus cavernosum? I don't know what to do and I'm tired of not being able to enjoy penetrative sex.

YES! They're called Kegels and they're easy and simple to do. No nudity required, no one can even tell you're doing them! They help increase blood flow and, most of all, strengthen your PC muscles.

Here's a good site for explaining what they do and how to do them.

Jelqing can help too, but go with the Kegels first and see how they go.

Oh and you'll shoot farther and more forcefully too!