I used to be a one cum only, but found my self abstaining from masturbation and watch porn, while at the same time did some edging, and strengthening the kegal muscles, and massaging the prostate
One month later booked an escort, and had two amazing orgasms, first ejaculation was a whopper, and around 20 min's later was ready for round 2
I can only say, this worked for me, might not work for everyone, but think overall guys can improve there erections and ejaculations, but have to keep at it, and a lot of this was done through experimenting