Exactly so, Davies. If you really, really want a happy ending or more, go to a place which is well reviewed as providing them.
If you're TOFTT , by all means take the extra cash with you, but be prepared for a legit massage ( which is what you initially paid for anyway).
The majority of massage establishments will never discuss extra services over the phone. They don't know who you are could be plod, local council, local busybody....anyone.