Chakra Sensations
The sensations you will feel in your chakras can vary, according to the degree of activity occurring in them, i.e., you're physical makeup, natural ability; concentration and relaxation skills affect this. It can vary from gentle warmth, a localized pressure, or bubbling (like stomach wind), localized dizziness, a tingling, a gentle pulsing, to a heavier throbbing, or a combination of some or all of the above.
The heavier these sensations, the more active the chakra will be. If you place your hand on a chakra, when it is active, you will actually feel the flesh pulsing.

Some of the chakras, when active, can cause other odd, localized sensations:

Base chakra: You may feel a very slight burning or tingling, or cramping, like you have been riding a bicycle for too long, to begin with. Once it is working properly, you will feel a gentle pulsing or throbbing between your legs, at the site of the chakra.

Solar Plexus Chakra: This can sometimes cause shortness of breath feeling, which can cause you to hyperventilate. This will pass, with time and use, as the chakra stabilizes.

Heart Chakra: The heart chakra merits special mention due to the strong, and sometimes frightening, the sensation it can cause. When this chakra is strongly activated it can feel like your heart is racing at a fast rate. It is a powerful sensation. Try and ignore this when it happens, it won't hurt you. It is not your heart racing but the chakra working. I know this is easier said than done, ignoring it, but with practice and familiarity, you can. This racing is more apparent in the early stages of development. I think this is caused by a lack of energy flowing from the lower centers. In a way, it is like a pump racing when it does not have enough fluid to pump.

The heart chakra, when fully operational, feels like: Place one hand on your chest, with your fingertips resting in the middle of it over your heart. Tap your fingers on your chest, in time with your heart. Increase this rate until you are tapping as fast and hard as your fingers can move.

Note: Your actual heart rate does NOT speed up with this racing sensation. If you hook yourself up to a heart monitor, you will see that your heartbeat hardly changes at all.

Throat Chakra: The throbbing in it can cause a very mild choking feeling, because of the sensitive area it is in. This feels something like having an emotional lump in the base of your throat.

Crown Chakra: When fully active it feels like a thousand soft, warm fingers gently massaging the inside of the top of your head, above the hairline, and extending down in the center of the forehead, to include the brow chakra, which is part of it. This sensation is the reason the Buddhists call it "The Thousand Petalled Lotus".

Note: You may feel a stronger sensation in some chakras and little or none in others. Concentrate on the lowest ones with the least sensation. This will help balance the energy flow in the Chakra systems.

If you are unbalanced, during projection the inactive chakras can cause failure, i.e., you may get your body partly loose but find you are stuck to your body at the site of the inactive chakra. If this happens, concentrate on stimulating the inactive chakra prior to projection.