I don't know why, but I gain a lot of pleasure from making a girl cum. This is why I prefer a girl who allows fingering, as given time most will climax with oral stimulation of the clit and a finger rubbing the G-spot. Far fewer will climax through penetration. One girl admitted to me that she couldn't climax through penetration alone, but this wasn't to tell me that she wouldn't cum, but just to warn me that she was going to rub her clit madly whilst we were shagging. Great experience, but now sadly gone back to resume her studies in Hungary.
As I was circumcised when I was about thirty, the combination of this, age and condoms means that I'm quite a stayer (often 20 mins) and very occasionally don't manage to cum at all. However I'm almost guaranteed to climax if the girl is cumming too. Fortunately my regular does cum through penetration (she starts to have a confused look on her face as she starts!) and there is no better feeling than releasing your load into a contracting pussy (not bb of course). I guess that's one of the advantages of a reg, she is more relaxed and you know how to press each other's buttons. Another girl, who is becoming a reg, told me that she can only climax once a day, but if I make her cum she becomes very sensitive, can't touch herself and has to limit the amount of oral I can give her in 69. I know it sounds a bit fluffy, but because I can (appear?) to make them cum, it gives me a great deal of pleasure too, and this us why I go back to them.
PS I've reviewed all three girls on here, so won't give their links again. It's obvious from the reviews which ones they are if anybody happens to be that interested..