Gentleness has its place so does roughness. Just like having your back scratched. Sometimes a soft light scratch will do, other times ya need a lot of scratching and kinda hard to. Different times and different needs call for different scratches.

Ask her how rough. When you are doing whatever it is you are doing, simply ask her ...harder, rougher, more. Follow her lead. If she says yes them proceed. If she seems content with that great, you can ask again if you feel same thing. (go with what you feel comfortable with, and what she wants)

I would ask her in advance, don't wait for her to say "Now stop that." Sometimes during sex one is unable to speak or say whole sentences. Have a safe word and a safe motion. A color maybe, or a kind of food, something totally unrelated to sex, or snapping your fingers, or whistle.

You don't have to be a tomboy and have guy like qualities to like it a little rough. Us ladies are ladies not delicate flowers or pansies.