Mike, I gather you are asking about increasing both the strength or intensity of an orgasm as well as the volume of ejaculate, correct?

This question has been asked many times. Keep yourself well hydrated, first and foremost.
Second, in order to increase volume and intensity, you have to enjoy fewer climaxes during the day/week. For example, if you masturbate three times a day whether all in the same session or spread out throughout the day, each succeeding orgasm will be more difficult to trigger than the previous and will have less intensity and volume of output.

This becomes a management problem between masturbating (or having sex with a partner) between needing to relieve sexual tension and one of simply to enjoy the moment. The trick is to know how many times you can masturbate in a day before your body refuses to respond for several hours and then to divide this number between how many times you want to do it for the simple pleasure of it vs. the need to do it. Hopefully you will not overdo the former and not have enough reserve for the latter.

If you do you will no doubt be on edge and antsy for several hours to a day and this can disrupt concentration as well as mood. If you do masturbate too often and/or have sex too often, then in order to replenish your "tank" so to speak, it will probably require abstaining for a couple of days.

I have found that sufficient stimulation throughout the day, minus orgasm, intensifies the orgasm when it finally hits that point. I have had the most intense orgasms on days such as this. We men sometimes want everything too fast and are not wanting to build up to the climax. Take it slow. Wait. Be patient. and when it comes...hold on.