Well, let me allay your fears. For me, being inside the vagina is LESS intense and I orgasm slower than if I MB. And, my girl friend used to screw me up
because she would sense that I was getting ready to orgasm and was trying to stop thrusting and she would bring me off every stupid time.
The reality is, most women cannot orgasm from intercourse alone, anyway. They require clitoral stimulation in order to orgasm. So, that being the case, with most girls that you encounter, it is going to be a process of giving them their orgasm(s) first through manual or oral stimulation, then proceeding to the intercourse phase. And it is not going to matter so much if you orgasm quickly, then.