Just be open and honest about what you'd like.  I'm sure she's heard it all before and if she's willing to do whatever you want, she'll discuss it with you.  If not, she will not likely be upset that you asked, unless she explicitly says that she does not do it at all.  Jst be polite and considerate when you ask and all should go ok.  You may not get it, but you also should not affect your relationship with her.