The best orgasms have to clit and spot inside the vagina both stimulated at the same time. I would recommend oral first, then plenty of silicon lube, man on top, her legs up until she gets her hip the angle she needs, go at a medium and steady pace...do not speed up unless she asks you too, do not go deeper until she is ready.....
My wife and I were just talking about this actually. She will only cum with me inside her. She will let me bring her to the edge, but jump on and ride so she can cum. In the 7 years we have been together, she has only cum without me inside her maybe 5 times.. For her, she would rather not cum.. I don't understand it, but that is what she prefers..
It's all in the teasing at the entrance. Pop the very tip of my glans in and out and when I finally work my whole head in, it happens
...egg vibrator on the clit while I slide in and out of her helps her to cum. That littel egg makes her fuck the shit out of me; love the egg!