start/stop engine

My 2010 Buick Lacrosse recently started having cranking issues. It start out of the blue, got into my car a couple hours after driving and my car wouldnt crank. Figured something was left on and got a jump. It didnt start right away, it took several tries. After being jumped, I drove home and...

.... do you hold it for a second or two until it starts up or stops, or do you just push it quickly and immediately let go and then wait for it to start? At first I held it in for a bit, but now realize it seems to start if you just push it in for just a split second and let go of it. Do you...