Walking up and down stairs! And if I can't, just standing and doing knee to chest lifts (mimicking using the stairs movement) helps too.
Prior to my rectal cancer and IBS-like symptoms as a result, I used the stairs to get up belches. I remember having heartburn with one of my daughter's pregnancies and then years later, I had heartburn because I had gall stones (had GB out with my colon resection). So I tried the stairs trick to release gas or help it along. It does work.
I also take my hand and massage my entire large colon track, on my stomach. A nurse gave me this suggestion. I have no idea if this works or not, but I've done it ever since. She said to direct the gas up, over, down and then out. Maybe it's a mind trick but it does seem to help me also. Odd though I know. I can't do this in public!