First, Leap of Faith is a stupid name. You’re not leaping anywhere. “Life grip” is the proper term to use.
That said, we often forget we have life grip, which is why you need to practice. A good time to practice is when you get suckered into healing a guild instance that is below your level but you agree to heal it anyway because “OMG pleaaaaase don’t make us take an LFG healer please pleaseplease!”
Try to use life grip whenever it’s off cooldown. It’s a good way to reposition the ranged DPS, or the melee dps who is getting too much threat. Don’t mention that you’re doing it. See if they can figure it out. Then giggle.
Pro tip: if you have body and soul, they will probably figure it out quicker because they’re going to be getting the body and soul speed buff whenever you YOINK. Stealth-gripping requires speccing out of Body and Soul. Like I just did. Tee hee.
Further Reading: Pugnacious Priest’s Leap of Faith Can Be Used For Evil Too.