The longest sessions I have had were all 90 minutes. Although I am MSOG's were available, I never tried it. Umm... no wait, I did try it. Well Cherise tried it more than I did .. but it didn't work. But not for lack of effort on her part though. Like Holkeft, I am an older guy and I like it slow and sensual. I love being on the peak of pleasure and sensuality and staying there. But I digress... .
You have to have a good chemistry with the sp. I would recommend you pick someone you have seen before and enjoy her company. You don't want to be in a situation where once the storm passes, you look at each other with "80 more minutes to kill... yawnn.. " look in your eyes.