"I can't imagine how she handled several hour sex"
Answer: Good silicone lube
ranukam, it just takes practice. Lots and lots of practice. Daily practice with a real live woman. Multiple different women. Basically, the bigger a male whore you are then the bigger sample size you have and the more you learn different techniques women like. I remember when I was younger I only knew one speed. Deep, hard and fast. Those first few dozen in my college years had to be seriously unsatisfied because I was an idiot.
15-20 minutes seems really short to me. You've got a naked woman in front of you. Why wouldn't you want to at least spend 30-60 minutes or more pleasuring her? Kiss her all over, rub her all over. Pick somewhere to start and just work to the other end. Rub her shoulders and work down to her feet or vice versa. Do the back then do the front. Get a nice edible massage oil. When DATY pay attention to her clit and get 2 fingers in there. Get them deep and press up with either a "come hither" motion or rub in a circle. Some women can cum from just oral and some can't. Some like a finger in their ass and some don't. It's up to you to test the waters and see what the response might be. You have to listen and watch. Watch her facial expressions, body language and listen to her breathing.
If you don't have one I suggest you buy a wedge pillow. Buy an actual Wedge and not a foam knock off. The Wedge Liberator is perfect and slides right under the end of the bed when you're done. Sex in a bed is a horrible position. The mattress gives a little so you're pointing down when you actually need to be angle UP. This is near impossible to do and what really tires most guys out and makes them finish too quick. The wedge raises the woman up off the bed about 8 or 9 inches to a height where you're pointing up and you can go deep and hit that G spot every time.
Then eventually when you find the one who blows your mind and makes you want to settle down you should be an expert in bed. i always say that marriage license; mandated by church and state, is a legal document that says a wife should be a whore and a husband should be a stud. If they're going to require that piece of paper they have no say what we do together afterwards. Nowadays, we can go for 2 hours no problem. You can still go deep and hard but save the fast until the end when she's begging for you to pound the fuck out of her. Yes, I could cum at any time but i enjoy spending as much time as possible satisfying mrs sea. The journey is just as enjoyable as the finish. Making her have a dozen or more orgasms is amazing and something that happens a lot. I'm not saying it happens all the time. Sometimes you just have time for 15 minutes and sometimes you've only got time to do a 5 minute quickie. The point is to focus on her completely and if it's a healthy relationship (even if she's just a fuck buddy or FWB) she'll focus on you as well. Just take your time and go at a medium continuous pace.
As for someone who refuses to suck dick....she just needs to hit the road. If she just wants dick in her and for you to make her cum and she refuses to do anything you like she's really not worth it. If she's a solid booty call you know you can call at a moments notice late at night when you have no other option and just want to cum then keep her # but I wouldn't waste any money or extra effort on her.
As far as specific positions; holy crap that would be a LONG post.