Dude, the best way to figure it out is to do it, the first thing i smoked was a bong, (i thank it for getting me fried the first time i smoked)
and while taking my first hit i didint suck hard enough, but beware sucking too hard on finer grinded weed will probably result in your bowl getting sucked into the bong water, oh yah, the tighter the bowl is packed the harder you'll have to suck, the looser the bowl is packed, the less you have to suck, SUCK AT YOUR DISCRESSION.