[QUOTE=FreeSeeker;5355396]Ok, I'll stick to the 30 minutes most likely then.[/QUOTE]If your goal is two shots, I wouldn't try 90 minutes HOPING that will happen -- I would ask a girl you already know ahead of time, perhaps at the end of a successful regular session, if she would do that for you if you book her for 90 minutes next time and tip accordingly. You will probably not be the first person to ask her that and she will probably be happy to comply to get you to see her again (provided she likes you). If it's just about getting two shots and you can do that in a 60 minute session, she would probably be okay with that too, it just has to be discussed in advance.
Personally, 90 minutes is something I occasionally do with specific girls in situations when the extra time would be useful. That includes enjoying the massage itself and then having plenty of time to enjoy extras that might go beyond the standard. To put it another way, I would not do 90 minutes just to get 85 minutes of massage and a 5-minute handjob.