If she’s over-staying her welcome and you’re really too intimidated to tell her to go home than tell a little ickle white lie.
“I’m going to see my nan tomorrow so you’re going to have to go back home tonight, sorry!”
Just something small like that.
I’d also like to just say, if she’s being a total bitch to you than she’s not much of a best friend. I think you need to really tell her straight that she’s being a bitch and you’re not going to put up with it. People like that don’t take no for an answer unless you dent their ego a bit.
Hope this helps:-)