Eating something like bread before drinking alcohol will line your stomach, also drinking water between each alcoholic drink will make it less likely that you are sick or get a hangover. Mixing milk and alcohol is more likely to make you sick as the milk will curdle.
Belching, also known as burping, is the act of expelling gas from the stomach out through the mouth. The usual cause of belching is a distended (inflated) stomach caused by swallowed air. The distention of the stomach causes abdominal discomfort, and the belching expels the air and relieves the discomfort.
Stomach flu (gastroenteritis) is almost always caused by an infection. The infection can enter the body in different ways. Drinking contaminated water is a common cause and sometimes the infection may enter the body because of poor personal hygiene (not washing your hands after using the toilet).