Basti basically a cleansing technique used to purify intestines.
Two variations Jala Basti and Sthala Basti
Jala Basti Technique (Yogic enema with water):
Remain in the naval deep water, insert index or middle finger in the anus by the process of chakri, and fill up the abdomen with water sucked through the water until once capacity. Wait for sometime and expel it out through anus.
It is to be noted that practice of Chakri (one of the kriya as per Hata Ratnavali) before commencing Basti.
Sthala Basti Technique (Yogic enema with without water):
Being in vipareetha karni mudra, bending the knee until chest and suck the air through anus and hold as long as possible and expel out. This can also be practiced adopting paschimottanasana (seated farward bend) but one must have prior knowledge of uddiyana bandha.
Stimulates gastric fire
Improves digestive disorders like constipation, indigestion
Enlargement of glands and spleen.
Brings about a deep sense of well being removes disorders caused by vata pitta kapha.
Note: To perform this kriya one must know how to practice Bandha (uddiyana) and Nauli kriya.