Do not bring it up on the initial visit.  On any subsequent visits just ask if she minds you doing it alone or if she'd like to join you.

If that was mentioned on an initial visit I'd be suspicious.  

I personally do not partake but am not opposed to others doing so.  It makes me sleepy.

I have had several clients offer, I personally decline, just not my thing, but I dont mind if they do, as long as I dont have any anxiety about the client in general.
Kisses
Winter

Never hurts to ask....

I know some that do and some that don't... get to know the gal and go from there...