I believe I have that answer - most of the time the 'ladies' arent in the mood for sex when the guys are - therefore, foreplay has to be brought in to allow the woman to enjoy it. The spontaneous things I am talking about are most of the time initiated by the woman. She is already warmed up toi her peak and cant hold it in and just wants hers, much like the guy always is. So she can very easily get off within minutes, much like the guy. And plus - the whole doing it in a public place turns them on even more so then its just better from the start at that too. Also when these spontaneous adventures happen it isn't some slow, soft, enjoy every second thing... its more like a all out **** fest, where you are pounding the shit out of her as hard as you can and as deep as you can. The both of you are just ****ing as hard and fast as possible it is kinda hard to let it last long at all for either partner.
But then again... I could be wrong... but I seriously doubt I am not far off base here...