Usually they ask you, if you've ever been here or not. Simply say no i have not been here but I've been to many massage spots. That usually eases the girl and she tells you about the xtra services. Or just politely ask if she offers any extra treatment..
While she's working on your back, be friendly and sociable. When she moves you for a chest massage you can politely make any special requests. I usually want extra time on my legs.
Thanks! Your answer is awaiting moderation.