One of the most popular beliefs is that the longer it takes to have an orgasm the more intense it will be when it occurs. While I have found this to be true to some extent, I have also found that if the sexual experience is not to my liking all that much then it does not really matter how long it takes. It will still not be the most intense of orgasms.
The most scientifically-based idea on how to intensify orgasms that I have come across is the study which concludes that it is a physiological thing Meaning, it will depend on how much oxygen there is available to the nerve endings which will determine just how intense a persons orgasms will be, on average.
This type of view on how to intensify orgasms is in my opinion based on a relatively sound fact. If the person has more oxygen in their blood then it will be more likely that they will have more nerve endings firing and be able to transfer the signal from those nerve endings to the brain in a much more efficient manner.
The ways in which you increase oxygen content of your blood go up will have many other health benefits other than intense orgasms, such as better stamina and less heart disease and respiratory illness.
Exercise is the most common way to increase the rate of oxygen in the blood but there are many other ways to do it as well. The Indian culture has been using meditation and yoga as a way to intensify their orgasms for thousands of years and I do not think that they would keep it up for that long if they were not on to a winner. Their method of how to intensify an orgasm is called "tantra" and there is a lot of good literature on this subject out in the ether.
The Asian culture has been doing it for a long time in the form of herbal methods to intensify the orgasms they have, and there is a good basis for what they have been up to as well. The herbs they use, of which ginseng and ginko biloba are most popular, are clinically proven to increase blood flow and improve circulation. These orgasm intensifying herbs are on the market to us in many forms, one of which is called a penis enhancement patch.
If you want to know how to intensify orgasms, the best bet would be to look for all of these things on the net and try them for yourself and see what works for you. If all of them work for you then life is going to be that much sweeter!
A concrete study on how to intensify orgasms is probably never going to happen in this life time for the reason that it is too hard to study. So do your own homework and find out what works for you!