What is the best way to summon Bloody Mary in a public bathroom?

We have drama rehearsals today, and the tenth. I've been wanting to summon Bloody Mary, because one of my online friends says she's haunting her school and I wanted to try, whether or not it'll work.

I know it could be bull crap, but I though if I could get to the bathroom it'd be fun.

Problem? i'm not sure if I say her name 13 or 3 times, and will a flashlight work for a candle, because I can't get a candle into a school and light it.

And how do you get rid of her?

Do I need to spin, if so, how many times?

Can Bloody Mary come out of the mirror to haunt, or will she stay in the mirror?

The answer I find most efficient'll get 3 Answer props.