This may sound similar to this question, but it's not the same.
This practice appears to be similar to the Khecari Mudra of Hindu yoga, but it's not the same, because the tongue need not be inserted into the nasal cavity. It is sufficient if it is pressed against the roof of the mouth.
This is based on the quote below from the Vitakkasanthana Sutta.
My questions are:
- Since this appears in the Pali Canon, do contemporary Theravada teachers teach this?
- How does it work? Does it stimulate certain nerves?
- Is this considered a last resort to controlling the mind, or is it a regular part of Buddhist practice?
"If evil, unskillful thoughts — imbued with desire, aversion or delusion — still arise in the monk while he is attending to the relaxing of thought-fabrication with regard to those thoughts, then — with his teeth clenched and his tongue pressed against the roof of his mouth — he should beat down, constrain, and crush his mind with his awareness. As — with his teeth clenched and his tongue pressed against the roof of his mouth — he is beating down, constraining, and crushing his mind with his awareness, those evil, unskillful thoughts are abandoned and subside. With their abandoning, he steadies his mind right within, settles it, unifies it, and concentrates it. Just as a strong man, seizing a weaker man by the head or the throat or the shoulders, would beat him down, constrain, and crush him; in the same way, if evil, unskillful thoughts — imbued with desire, aversion or delusion — still arise in the monk while he is attending to the relaxing of thought-fabrication with regard to those thoughts, then — with his teeth clenched and his tongue pressed against the roof of his mouth — he should beat down, constrain, and crush his mind with his awareness. As — with his teeth clenched and his tongue pressed against the roof of his mouth — he is beating down, constraining, and crushing his mind with his awareness, those evil, unskillful thoughts are abandoned and subside. With their abandoning, he steadies his mind right within, settles it, unifies it, and concentrates it.