Need Advice & Tips

So I’m 28 and I’ve been sexually active since I was 24.. I’ve been with 3 guys all different sizes and I still can’t seem to “climax/finish” I get close when masterbating and during intercourse but never “ring the bell” my whole body shakes and goes numb.😕

I’ve tried several different things in the bedroom area but I can’t seem to find the right way to release to get my O.. can anyone relate?

Advice and tips needed.