Back2Yourself

best is that Engage and lift the pelvic floor muscles when you draw the navel towards the spine. This is done when you establish the setup position for and during the practice of the exercises. Pelvic floor engagement may seem rather elusive; engagement tends to disappear when our attention is directed elsewhere. No sooner than you have engaged the pelvic floor, it is relaxed when you bring your attention back to it.

Yes, you may exercise more than once a day. See the forum post from May 6; always maintain proper alignment and muscular support. If you feel muscle fatigue when maintaining proper alignment and support then it is not a good idea to continue to exercise. Rest and try again or wait until the next day. It is ok to exercise more than once per day as long as it is done carefully and safely to prevent injury.