I'm 4 days postop and can't burp. Do the yoga position "downward facing dog" and it will help the gas come out your other end. And wiggle side to side to help it out. I know it's not lady-like at all, but it's so painful otherwise! If you can, sleep on your left side, it helps the gas get out easier. I'm a nurse and when we have to give enemas, we make patients lay on their left side - helps things come out easier.
Good luck!