Vedananupassana: This exercise is an aspect of the mind. Practitioners must always try to see the body and the mind apart. Feeling arises due to outside world contacts with the mind. Feeling causes a problem if we are under the influence of the feeling. So, when any feeling arises, practitioners watch it and allow it to pass by. In the Sutta it says:
"And how does a monk remain focused on feelings in and of themselves? There is the case where a monk, when feeling a painful feeling, discerns that he is feeling a painful feeling. When feeling a pleasant feeling, he discerns that he is feeling a pleasant feeling. When feeling a neither-painful-nor-pleasant feeling, he discerns that he is feeling a neither-painful-nor-pleasant feeling.
"When feeling a painful feeling of the flesh, he discerns that he is feeling a painful feeling of the flesh. When feeling a painful feeling not of the flesh, he discerns that he is feeling a painful feeling not of the flesh. When feeling a pleasant feeling of the flesh, he discerns that he is feeling a pleasant feeling of the flesh. When feeling a pleasant feeling not of the flesh, he discerns that he is feeling a pleasant feeling not of the flesh. When feeling a neither-painful-nor-pleasant feeling of the flesh, he discerns that he is feeling a neither-painful-nor-pleasant feeling of the flesh. When feeling a neither-painful-nor-pleasant feeling not of the flesh, he discerns that he is feeling a neither-painful-nor-pleasant feeling not of the flesh.
"In this way he remains focused internally on feelings in and of themselves, or externally on feelings in and of themselves, or both internally and externally on feelings in and of themselves. Or he remains focused on the phenomenon of origination with regard to feelings, on the phenomenon of passing away with regard to feelings, or on the phenomenon of origination and passing away with regard to feelings. Or his mindfulness that 'There are feelings' is maintained to the extent of knowledge and remembrance. And he remains independent, unsustained by (not clinging to) anything in the world. This is how a monk remains focused on feelings in and of themselves.
Vedananupassana - Luang Phu Mun, Pinayo Prommuang
Translated by: Ven. Thanissaro