Before attempting basti you should master madhyama nauli. This is necessary in order to suck water or air into the colon.
Water and bath
For air basti no water or bath is required. For water basti you will have to sit or stand in a bath of water. The water level should be such that it is just above the level of the anus. The depth of water required will depend on the sitting position. That is, if you sit in paschimottanasana then five to ten centimetres is sufficient. On the other hand, if you stand in utkatasana the water will need to be much deeper.
The water should be neither excessively cold or hot. If you have sufficient time then you can dry of all use warm water (about body temperature – 98° Fahrenheit is ideal). This warm water will loosen hard encrusted stool from the walls of the colon. Then you can use cooler water not freezing); this will tone up the nerves of the colon and anus and will stimulate the blood circulation. This will be very useful if you suffer from piles or constipation.
There are many other types of herbal enemas that can be used instead of water and air. They can be used for specific needs. Generally, however, water or air are more than sufficient.