Flatulence in public can be embarrassing, especially if you are locked in, say, in a concert hall. I don't find it difficult to plug the release for a while. The pressure usually drops after a few minutes. However I wonder what happens to the obnoxious gases. Are they released at a rate below the detection level of most human noses or are they adsorbed in solid waste? I did some internet searches, but the research papers usually deal with methane, which is irrelevant because it has no odor.
They are mainly certain sulfur compounds that cause smelly gas (Gut, BMJ Journals):
...organic sulphides of bacterial origin, primarily methanethiol, dimethyl disulphide, and dimethyl trisulphide, were the primary malodorous compounds elaborated by faeces.
The cells of the large intestinal lining can break down hydrogen disulfide into dimethyl disulphide (PubMed), "which...probably plays little part in flatus malodour" (Gut, BMJ Journals). This means that holding gas would give hydrogen dioxide more time to break down and thus reduce its smell.
Avoiding foods high in sulfur (meat, fish, almonds, dates, broccoli, cauliflower, Brussels sprouts, cabbage) can decrease the smell of the gas (Gicare).
So, theoretically, holding back gas could reduce the smell of the flatulence.