My friend is absaloutley disgusting?

Hi I'm 14 and my friend makes me feel ill but I don't know a polite way to tell her that she has some BAD issues, she is bisexual and will take any chance she has at flirting, weather it is with her cousin or me, the other day she invited me over to her house for a sleepover and while we were in her room she took off her Jammy bottoms, farted in her hand and started sniffing it, in bed I heard a squeaking , wet noise so I turned on the light and climed up the bunker to see that she was massaging her vulva and holding her breath , she was just lieing there rubbing her bacon bit, in the morning she said she needed a crap so I told her just to go to the loo, instead she put her fingers up her *** and started eating her poo as if it were chocolate cake, I asked her why she did these things and she says she does it everyday, in school the next morning she started picking her nose like proper diggin in there and eating it like custard on cake, in art she started scratching all of her dandruff and eating it out of her finger nails, then on Wednesday she got up from her chair and left a puddle of piss and her skirt got caught on the desk and she had blood on her nickers, what can I do?