Hey, Olive. First, rape is never the victim's fault remember that.

Those guys are into the whole justifying rape thing known as "rape culture"; they put the blame on victims rather than the assailant. It's wrong, and the way you dress does not define whether or not you're rapeable. Because we have the freedom of expressing ourselves through the way we dress.

However (I'm not sympathizing with rapists here) you have to know the line where decency and indecency meet. You don't want to dress so your butt cheeks are showing or your nipples can be seen. It's not up to me to say you have to wear underwear or bra, but use your judgement. But you still have the freedom to dress however you want!