I was having the same problem, then I found this helpful info online. I quickly started seeing results.
1. Start by standing up.
2. Lightly tighten you stomach muscles. (A.) Suck in Your Gut ...Or... (B.) Firm up Your Stomach by Pushing Down, Try Them Both.)
3. Hold them lightly tighten.
4. Then take slow, deep breaths, in and then slowly out, all the while holding your stomach muscles tight. After 7 or 8 breaths you will feel the oblique abdominal muscles begin to be recruited, then the lower and upper abdominal’s being slowly synched tighter ALL without any more effort than the initial light muscle tension. You can do this toning exercise Anywhere !