Some people are very concered about how much they ejaculate, and how much force it comes out with...Inluding how far it tends to go, as well as the orgasm intensity.

Let me start out by saying that you should be happy with what you have. Girls and guys do not, or at least should not, care how much you can ejaculate.

Now, some people say it just isn't possible to increase the intensity, but I think otherwise. I am spliting this topic into two sections: "How" and "Why"

Section I

The male orgasm/ejaculation involves the contraction of many muscles in and around the pelvic region. Because these muscles don't always get excersise, they can become weaker, resulting in a less powerful ejaculation. This is the same reason why some people cannot get full erections.

There are a couple ways to gain better orgasms:
1.] (a somewhat passive way of doing things) A guy who is already sexually active, and continues to be sexually active is already working those muscles a great way. (I am assuming this includes masturbation) Since the muscles are in good shape, the guy does well gaining an orgasm, and therefore has greater confidence.

2.] Another, more active, way of doing things is excersising the muscles around the penis yourself, especially the muscle called the pubococcygeal muscle. Some studies note that men who exercise their muscles actually can sometimes with-hold orgasms better.
The best exercises to do are proabably the kegal exercises. I found on a newsgroup a great question/answer about kegals.
Question: What are Kegel exercises? How can one increase the force of ejaculation?

Section II
Kegel exercises (pronounced "Kay-gill", in case you ever actually have a
conversation about them) were invented to give women better bladder
control. They have a number of useful advantages in sex. In women, they can
help tighten the vagina, particularly after childbirth. The muscles can
also be used deliberately during intercourse to stimulate her partner. They
have a variety of uses for men. As I already mentioned, they strengthen the
muscles used in seminal retention, making that technique more effective.
They can make ejaculation more powerful. This may increase male enjoyment
somewhat and female enjoyment if she is sensitive to it. Deliberate
twitches during intercourse are also useful for males. Knowing how to force
relaxation of the muscles can help maintain control and prevent premature
ejaculation, as well as relieving the muscle cramps that can occur from too
many ejaculations in succession.

Kegel exercises might indeed help with [increasing the force of
ejaculation]. Here is how they are performed by males. First you have to
learn to consciously control the muscles. One way of doing this is to use
them to stop and start urination repeatedly. When you have an erection,
contracting them causes it to move, making them easy to identify. Once you
have the muscles identified, there are three types of exercises to do:
1. try contracting the muscles and holding them that way for a slow count
of ten. You may not be able to last that long at first, but that is why
you are exercising.
2. force them to relax by bearing down as though you were constipated and
trying to force a bowel movement.
3. twitch (contract and release) the muscles as fast as you can ten times
in a row. I find that it works well to alternate each of the first type
with one of the second type. I don't recall how many of these are
recommended. Something like ten of each to start, eventually working up
to a hundred.

In addition to the possibility of increasing the force of ejaculation,
these may increase the number of contractions and the total enjoyment. The
same muscles can also be used to reduce the amount of semen in an
ejaculation by contracting them as hard as possible during it. This leaves
a less than satisfied feeling, usually accompanied by an urgent desire for
another orgasm 10 to 20 minutes later. This can be useful if your partner
wants more sex than you do. Supposedly, increasing the strength of the
muscles can increase this effect to allow quite a few orgasms in a row.
This is the only way that I currently know of, as I really don't pay that much attention to how to increase my ejactulations. (I'm happy with what I have. )

I feel this information is valid, though, and is safe. If anyone tells me otherwise, I will immediately remove the topic. But keep in mind...all should be fine, I just always try to put disclaimers on medical-ish things.

Parts of this article come from: