How to have a stronger orgasm?

Not going to lie, and don't ditch it till you try it.. Anal masturbation.

Yes, I know for a heterosexual male, this seems really
weird, and out of the ordinary, but anal masturbation along with
the standard masturbation can be a lot more potent.

I would suggest getting a anal plug (of small size to start with)
to just have while you masturbate.

Before you ditch it for the weird "abnormal" masturbation style, you should
at least consider it. You will get results ^-^

Just remember, be clean, be safe use a lot of lube, and relax while you are
doing it. Anyways, hope this helps.