What kind of sensations should appear during Pumping?
Sensations can be very different. Everybody has his own sensations, but the common sensation is the move of energy on and through the body. Try to analyze what is going on in your body during exercises. Sweet or acid taste in mouth, warm, cold, pricking, gravity in hands, or legs become numb, or back is tired, etc these are physical sensations and it is necessary to fix them to get the stable Consciousness position. Sometimes it is difficult to define by words the sensation. Then you can at least localize those sensations and say are they pleasant or unpleasant.
