Orgasm length as a variable of pleasure accepted in general.

[Liet]

This is not good info...ejaculate it mostly simple sugars and does not contain significant amounts of protein or anything else. It is far from equivalent to a four course meal, and the tiredness one experiences after ejaculation is not from losing the nutritional contents of a four course meal. "There are many possible factors (time of day, where one is, and the effects of relaxation, among others), but the most immediate reason is the release of chemicals in the brain, many of which are associated with sleepiness. I don't know what sources you got your information from, but you should get in the habit of cross-referencing them, since a quick search of the internet on these topics would have corrected your misunderstanding."

From Alex Murray commenting on the subject at hand.

The reason for tiredness and such is due to your solar plexus disposing part of its accumilated energies.
Having a higher maximum cap of energy within it, and faster recovery rate comes about with increasing its frequency.