In the beginning, beset by wandering mind, it may be expedient to struggle with the mind, body and breath.
MN20:7.2: Tena, bhikkhave, bhikkhunā dantebhidantamādhāya jivhāya tāluṁ āhacca cetasā cittaṁ abhiniggaṇhitabbaṁ abhinippīḷetabbaṁ abhisantāpetabbaṁ.
MN20:7.2: With teeth clenched and tongue pressed against the roof of the mouth, they should squeeze, squash, and torture mind with mind.
Yet although such practice may serve in the beginning, such practice disturbs the body.
MN100:17.7: My energy was roused up and unflagging, and my mindfulness was established and lucid, but my body was disturbed, not tranquil, because I’d pushed too hard with that painful striving.
One might even try to go further on this painful and dangerous path.
MN100:18.2: ‘Why don’t I practice the breathless absorption?’
MN100:18.3: So kho ahaṁ, bhāradvāja, mukhato ca nāsato ca assāsapassāse uparundhiṁ.
MN100:18.3: So I cut off my breathing through my mouth and nose.
But it is truly dangerous.
MN100:23.4: ‘He’s not dead, but he’s dying.’
This extreme practice is fruitless.
MN100:27.5: But I have not achieved any superhuman distinction in knowledge and vision worthy of the noble ones by this severe, grueling work.
MN100:27.6: Could there be another path to awakening?’
Right immersion is not stressful.
MN100:28.2: ‘I recall sitting in the cool shade of the rose-apple tree while my father the Sakyan was off working. Quite secluded from sensual pleasures, secluded from unskillful qualities, I entered and remained in the first absorption, which has the rapture and bliss born of seclusion, while placing the mind and keeping it connected.