My sweety enjoys multiple orgasms frequently. Its a wonderful thing. !!

I have orgasms without cumming and that you can practice. He needs to know when he is going to cum and stop the sensations in time to prevent ejaculate, but he'll get the orgasmic feel. It will take some time to get the hang of it. This makes the final orgasm bigger including the load. Now as far as cumming many times, that comes down to many things. I have noticed different things for myself like being rested, relaxed,sometimes alcohol, but if I could think of one thing, is that he has to be into the sensations the woman is giving him...it's got to get him excited. No distractions...been there done that.
Good luck
Mr S

You wanna know the truth? It boils down to breast fed babies. Breast fed babies grow up with strong teeth. I was a breast fed baby, and now I'm a breast fed man. Still got all my teeth every last one of them. You wanna keep the teeth you still have, start suckin titties. It ain't too late!
That may also assist the multiple orgasm in men.

So be sure to brush, floss and suck a titty before going to bed at night.

my man cums many times in a row he is great at starting to cum then stopping it over and over until the big final cum.

Probably because you let him take his time. My ol' lady wants that nut right now. I'm like damn girl slow down, savor that shit. Point is...
Let him feel comfortable in there, he ain't gonna wanna leave. Shit feels too good. Nut came out just right, he can go another round. Hell there were a couple times where I came without ejac and thought that was some tantric shit. Look, just be happy your duck lays golden eggs. Like you said, you might fuck it up trying to find out why.