For everyone the experience is slightly different, but here's a sample of experiences you might expect. Some people experience energy moving in waves throughout the body, particularly up the base of the spine to the crown of the head. This can often last for hours at a time after playing. You may experience vivid visual or sensate images. As you become more skilled you may decide to vary what you do.
Many people find that their skill level dramatically increases with practice.
This occurs when our unconscious begins to understand what the process is all about, and the inner path becomes more obvious and automatic, much like water flowing over the same ground creates a deepening channel over time.