This sounds like an interesting topic for research; we’ll get our best men on it right away.
Along these lines, I put a post in here somewhere the last couple of days about a new pharmaceutical, Cabergolin, initially designed for Parkinsons, which may increase male stamina and the ability to have multiple orgasms. The drug works by supressing the amount of prolactine in the subject. Researchers had observed a rise in prolactine in men after orgasm and inferred that perhaps the prolactine inhibited the ability to continue with performance. In test subjects prolactine levels are reduced. They also reported a better orgasm and shorter refractory period.
I do wonder how you get so sign up for these sorts of studies.