Someone asked: during meditation, there's sometimes an urge to burp or release wind, or to yawn, without feeling sleepy at all — what causes this? And also: yawning without sleepiness and tearing up almost every time, especially during chanting — what causes that?

These signs occur because impurities are being expelled. It's a process of distillation — separating unwholesome impurity from the mind. Once separated from the mind, it evaporates outward as vapor, as gas — which is why yawning and burping occur. All of it relates to impurity; it's the distilling and separating of impurity, evaporating out as vapor. The same goes for yawning without sleepiness and tearing up during chanting. Every dhamma practice is a tool for refining the mind — whether chanting, sitting meditation, or anything wholesome — all serve as tools that distill impurity out of the mind. Once that impurity has evaporated, it must be released, which is why yawning, burping, and tears occur — all arising from impurity evaporating out of the mind.