Actually, I consider myself still as a newbie when it comes to enemas. But to be honest, I have had that happen more than a few times, especially with the colon issues I had there for a bit this year.
I have to admit, encountering a gas pocket is rather painful, whether you are taking an enema or just have it rumbling around inside you. During that time I often had them really bad up under my rib cage making breathing not only difficult, but very painful as well.
My solution for this, and it works very well and usually pretty quick is to put myself in knee/chest position, meaning head down, butt up, and doing a little massage to my abdomen. Hot air rises, gas is hot air. So it makes sense that putting your tush in the air will cause the gas to head that way, towards your lower colon, then out your bottom. A little embarrassing perhaps if you are not alone, but it works. And forewarning, producing gas in this manner will not produce the normal girly poots, but often times will or might produce manly farts, you know, the stinky loud farts. Oddly enough, I have a whole med cart at my disposal with just about any sort of med like that I would want on it for a situation such as this, for example, gas X, gas ban, simethicone, tums, and mylanta, but sometimes when you are feeling like this, relief can't come soon enough.
Trust this nurse, knee/chest position works wonders for this, and soon you will be able to get you back on track to your enema playing sessions comfortably. Try it out a few times and let me know if it works for you, or what your thoughts are about this position. And hey, if you are into the embarrassment factor, well it's a double win for you, lol.
The other thing I have found that helps a little bit, and it's really hard to do when you are hurting is to relax. I know I know, easier said than done right? Also a hot water bottle/enema bag applied to your belly can also help that out a little bit from what I understand.
But good luck, and trust me when I tell you, I know how you feel.
Mashie