The usual hint is 'open minded'. This means the girl may be open to offers or willing to provide extras. However, this does not mean she will offer extras to every guy that comes in. Rule one is never ask at reception for extras. You should remember RNT shops are supposed to provide massage only not sex. What may happen behind closed doors is a matter between you and the girl. Most girls who do extras tend to mention it but many times after part 1 is done. This leaves less time for other juicy extras. On the other hand, you may bring it up early in a subtle way if you're keen on any extras.