Burping or belching? What is....

http://www.burpsandfarts.com/

Belching is more of an enforced roar, & is considered poor form in most establishments

Debretts gives the best guide on this matter imo:

Belching

[i]"to belch is mainly the preserve of the working and underclass and is often released "with force" after the part digestion of cheap cuts and/or low grade starches and sugars.It can (but not neccessarily) be accompanied by the shouting out of football player names occasionally in conjuction with the release of feceal gas.[/i]