No, you won't hurt him. I bet you are the same 'Anonymous User' that has asked this question several different ways recently, aren't you? ;-p Naw, it's cool though. But yeah you will feel it.
Are you talking with clothes on or off?
If you both are naked that boner will end up in you, if you are not naked it will find a place to get out of the way
You will feel it if he gets a boner when you straddle him sitting. If you wanna make sure to give him one, then keep working yourself down more and more until you you know your crotch is pressing on his genitals. Keeping this up for only a short time should produce the boner you want from him. Noo, heck no it won't hurt! It might feel a little uncomfortable for him depending on where his boner has worked itself but nothing for you to worry about. Besides, you'd want him to feel you and know that you're aware of what you've done. lol. Guys l ike that so just have fun.
He would probably have to adjust himself, but you won't hurt him at all..and yes you will feel him below you...just be gemtle and enjoy the position...I'm sure your boyfriend will...:)
If you sit on him, and he gets a boner, the boner will likely find a place of least resistance to move, so you wouldn't be crushing him.
Yes, you will likely feel it.
No if you straddle him you shouldn't hurt him but it would turn him on. And to really turn him on grind against it. Yes you should feel it.