I am a tai chi practininer.How the qi feeling could be described?

I practise standing qi gong gor 2-3 years.In a posture called "holding a baloon", i have a strange sensation that i hold an actual solid ball.Am i feeling my own qi (chi) ?Is that weird sensation what am i supposed to feel?

Not to be rude, and I almost never say things like this, but I completely disagree with the guy above me.
To explain it very simply, according to western science, if something cannot be sensed with one of the 5 senses, then it does not exist, and you can assume the preceeding is true with a religious degree of faith. Chi not existing is not "fact" it's simply your ideology. Who knows, maybe evolution is false too.
I do a lot of work with various Daoist practices, so I tihnk that I can answer your question.
*I wasn't sure exactly how to answer this, because something slightly different occurs in standing verses tai chi. I'll do both since I'm not sure which you want!
Basically, people feel chi differently. Normally it's through one of the following:
Heat (due to chi moving the blood, and you feeling heat from blood)
A tingly sensation or something similar to electricity (which is from the nerves getting activated)
A fluid rushing through your body, which is not "physically there" (this is just chi)
A pressure or force (this is from interactions with your outer layer of chi).
What you're describing is the last one. A ball between the hands/arms is one of the most common ways people feel the pressure from their etheric body (type of chi).
If you do it more, the force should become stronger.

I can't really tell you any more than that, because a lot of things with chi behavior are extremely dependent on the form and how you are doing it. The feeling of chi you should arrive at is where you can notice how energy flows through your body depending on what movement you do. The exact pathways that the chi follows depend on the form you are doing, hence, I cannot say what they would be. Some people who teach tai chi aren't very good, so they don't know much beyond things like building up your chi in general (so you can say feel things like a ball between your hands), but if you have a good teacher, they should be able to tell you what flow the movement creates and you can see if you feel it. Assuming you do that, at first you'll gain the sensitivity to be able to feel the chi flowing, and then you'll gain the ability to correct your movements so they improve the chi flow.
Standing Chi Gung is a bit simpler. It just tries to build up your chi (and make you be able to feel it in a different way). The biggest thing to aim for with standing is to be able move chi through your arms so they don't get tired (and then have the flow rise up all the wsay through the legs). When you stand for a while you'll start to notice various points hurt or ache, which means there is some sort of chi blockage within them. The goal with standing beyond building up your power, is to be able to loosen and open up these "chi knots."

Hmm...I think that answers everything you asked. Feel free to ask me if you want to know anything else!

Instruments for detecting EMR turn it into things which can be seen. I should have said that explicitly, but I assumed it was understood. There are many types of energy suspected to exist, which cannot currently be converted to a form which can be directly perceived with the senses. Report It

YEP YEP YEP, you should be feeling all these TAI CHINGs, they are good for your health! Keep it up!

i don't know.

yes. this ball is your qi. you should condense this ball, making it denser and smaller, and store it in your bone marrow. Once you fill your skeleton with balls of qi like that one, you will be able to direct all that energy.

I mean no disrespect, but Chi/Qi/Ki energy is a myth that's never been scientifically demonstrated. You may have seen some amazing things, like your teacher knocking over a student without touching him/her. This is a demonstration of psychological illusion. Both participants believe in a thing called "Qi Energy." They believe it exists and so they expect to feel it. They expect that it has force and can move objects. In reality, there is no force. The mind makes it real. What I mean is, there is such a strong belief that the energy is there, the body feels it. It's not actually there. The body just reacts because the mind strongly expects it too. It's all in your mind. A trick of the mind. It doesn't actually exist.

I know I lumped Ki in there as well. Ki is not actually the same thing. Rather, it is a method of exploiting weak areas of the enemy's body (eg. joints, groin, face). With knowledge of human anatomy, it is possibly to apply a very small force to these areas of the opponent's body and cause very big reactions (such as the enemy flipping over onto his/her back). There is no special energy force in this one, it's simple physics. Bend an opponent's wrist a certain way and the pain is excrutiating. They have no choice but to flip. Otherwise they have to deal with the pain and possibly a broken wrist.

I hope this was helpful. You may think I'm wrong because you have actually "experienced" a feeling. Well my post isn't a response to the feeling/spiritual side of Qi/Chi/Ki. Only the physical mechanics, physics, and psychology involved here.

To Alex F (message below): You wrote, "according to western science, if something cannot be sensed with one of the 5 senses, then it does not exist."

That is not true, and here are just a few examples: black holes, radiation, infrared light (in fact, much of the light spectrum).

You wrote, "you can assume the preceeding [sic] is true with a religious degree of faith"

I disagree. "Faith" has more than 9 accepted definitions. The one which describes religion is not equivalent to the one which describes scientific uncertainty. Furthermore, science is based on repeatable evidence. Scientific theory is always open to criticism and peer review. Here are some links to help you:
http://en.wikipedia.org/wiki/Faith
http://dictionary.die.net/faith

You wrote. "Chi not existing is not 'fact'..."

Neither is "Chi exists." However, since you are the one making an extraordinary claim(one would agree that telekinesis is not ordinary), the burden of proof lies with you.

That's great that you do not agree with me, but leaving it at a "thumbs down" would have sufficed..

I would think so.
We all feel our qi differently, mine happens to feel like flowing water.