Most websites and books go into too much detail concerning the bandhas. The following is a basic summary:
When the bandhas are applied during breathing exercises or when chanting, they act to amplify energy and/or direct it.

This is for informational purposes only. Personally, I dislike applying the Jalandhara Bandha [chin lock], as the serpent is supposed to ascend through the crown chakra at the top of the head and applying this lock keeps the serpentine energy trapped below the throat where it is applied. I personally don’t recommend this. There are corruptions in certain methods due to a failure on the part of the enemy to eradicate all spiritual knowledge and techniques. This can be seen easily with Wicca [Christianized Witchcraft] and related. Because all spiritual knowledge could not be removed, the enemy worked to corrupt a lot of it.

Both the anal "Moola Bandha" and the abdominal "Uddiyana Bandha" are effective in working to ascend the energy, as they should.

There are three main bandhas.

• The "Moola bandha"
• The "Uddiyana Bandha"also known as "The Abdominal Lift."
• The Jalandhara Bandha is also known as the"Chin Lock." This is applied by dropping the chin to the chest.