Can be used in 2 ways.
1) Use it casually when you want to get a feminine figure (hourglass figure)
2) Use it when you do cardio training. This helps to burn fat from your belly.
If you are one of the unfortunate 95% of male, then most of the fat is collected onto your belly! In that case, this product is necessary if you want to lose the belly fat quickly. See below image how girls use it.