How to defend myself with a groin attack?

I am a 20-year-old girl and I'm only 4'9" and kinda skinny so I want to learn to defend myself. My friend she told me the best way to defend against a guy myself is to attack his balls. I’ve never hit a guy down there so… is it as effective as she make it to be? What are some effective moves in different situations if I need to defend myself?
How to defend myself with a groin attack?
Post Opinion