A burp is nothing but gas. When we eat or drink, we
also swallow air. When we take more air while drinking
or eating, it comes out of the stomach through the mouth
as a burp. Drinking sodas or other gassy drinks makes
us burp more as these drinks contain extra gas. Sometimes,
you may eat too fast, taking more amount of air inside
and that too can make you burp.
Burp is a natural human process just as how you pass
motions and urine. However, due to good manners involved,
it is always considered polite to burp quietly and to
cover your mouth while burping. Also, avoiding spicy,
oily food may help. Not to forget avoiding sodas. And
mind you, over eating may also cause you to burp.