A recent comment pointed out you can't burp in zero-g, while we don't have anything here about it, a Google search seems to support the comment.
If you spin your body, in theory you could overcome the lack of gravity issue with centrifugal force. Plausibly causing gas bubbles to gather as desired. By positioning your arms, legs and or adding extra weight, you might even be able to influence where in your body they gather, in effect controlling which end of the digestive track the gas would exit.
Is this plausible?