You can also Rub your VK on the tummy where you feel to shape up. While rubbing you can chant BEAUTY SERUM or FLAB DOWN SERUM or GOLDEN SUNRISE. You can do this daily at least for few minutes.
Please Check Process 1, Example 3 in this article of Easy ways of doing VOB
One more suggestion you can change this thought
"Rigid Flab on my tummy not going whatever exercise i am doin" to
"I WANT A PERFECT BODY WEIGHT AND DESIRED BODY SHAPE NOW"
Remember VK is an INTENTIONAL tool, it listens to your clear positive intentions, when you repeatedly say Perfect body and Desired Shape, you will create more energy for this wish. Hold the image of your desired body shape …..in your mind.
Also by saying Rigid Flab not going , you might be attracting more rigidity on tummy from Universe.