After gaining skill in the recollection of the Buddha, the body will be regulated.

Yonggang asked: During my nap today, I heard the four-character Buddha's name being recited continuously, yet I was in a state between dreaming and waking; my vision was blurry, and though I wanted to open my eyes, I couldn't. But when my child spoke and left for school, I was aware of it. This state lasted for over an hour. After two o'clock I went out riding my bicycle around the streets, came back and did more than forty minutes of daily practice, then sat in meditation in the half-lotus position reciting the Buddha's name. Today I recited the six-character Buddha's name, reciting a bit fast, with the voice slightly louder than usual. During the recitation I felt my whole body tingling, numb, and swollen, especially noticeable in the head, and at the same time my chin trembled noticeably. Since the second half of last year, I have started burping when reciting the Buddha's name; up to now, whenever I recite the Buddha's name or bow to the Buddha, the burping is very severe, but when I am not reciting, I do not burp. Because Master said that wearing the Śūraṅgama Mantra wards off evil, I wore it during my nap. Please, Master, give me guidance and correction on what I should do next.  

Answer: Automatically reciting the Buddha's name in a half-asleep, half-awake state is preliminary recollection of the Buddha (buddhānusmṛti) by the manas, and there is some meditative concentration (samādhi) already. When reciting the Buddha's name while sitting in meditation, feeling the whole body tingle and go numb means the qi channels are circulating throughout the body. If there is some dampness or something else in the body obstructing the smooth flow of the qi channels, there will be a tingling, numb sensation; the qi channels are also circulating in the head. Burping while reciting the Buddha's name and bowing to the Buddha is a phenomenon of the qi channels reaching the stomach; as the qi channels circulate, they push the cold-damp qi in the stomach upward, producing burping. If everything below the stomach is open, with no blockages, the cold-damp qi in the stomach will move downward and be expelled from below, and will not rise upward causing burping. When the qi channels move further up to the lungs, there may be a lot of nasal mucus; if there is no blockage below, the cold-damp qi will be expelled downward, and there will be no nasal mucus.  

When there is meditative concentration, the qi channels circulate and will automatically regulate the body, producing various phenomena; all of this is normal and a good sign. If you want to open up everything below the stomach, you should breathe deeply, drawing the breath down to the lower dantian, and then breathe with the dantian—that is, abdominal breathing. This way the body will open up more quickly. Once the qi channels reach the lower dantian, the back and legs will open up quickly, the whole body will start circulating, the meditative concentration will become deeper and deeper, and the results of reciting the Buddha's name will get better and better. Poor meditative concentration is related to poor physical health, so you should regulate your body as well and as quickly as possible. Search online and you will learn how to deal with these problems. Having the internet is so convenient—make use of it right away.  

Wearing a handwritten Śūraṅgama Mantra on the body also has a blessing effect; everyone can write one or two copies of the Śūraṅgama Mantra themselves and wear them on the chest or upper body. Going forward, you can continue reciting the Buddha's name, cultivating the Buddha-recollection samādhi (buddhānusmṛti-samādhi), or use recitation of the Buddha's name to cultivate concentration. Once the dharma principles for eradicating the view of self (satkāya-dṛṣṭi-prahāṇa) are clearly understood, and your meditative concentration deepens a bit more, then engage in contemplative practice (vipaśyanā-caryā) on the five aggregates (pañca-skandha), or cultivate the contemplation of the white skeleton, striving to eradicate the view of self.