I don't think I've ever not had to pass gas with a plug in. It's not the most sexy thing to do, but it's going to happen. I can't actually pass gass with the plug in, or else it shoots out.
If you do it enough times, it'll be part of the process, neither of you will notice anymore.
You could hold it in and get crampy, but I doubt there is anything more you can really do.

I know some foods cause bloating and gas, by cutting down on certain things, you can minimize the gas.