Initially taken from http://www.reddit.com/r/Guildwars2/comments/17588c/psa_fotm_jade_maw_tip_reflecting_crystals_despawn/

• Reflecting crystals despawn after ~60 secs. Pick them up and drop them to reset the timer. You need to pick up and put down. Then timer resets. Crystals can vanish in your hands, so it’s important to do the full reset to keep them “fresh”.
• People rez’ing will often take target priority from the maw, however if you’re holding a crystal you can rez to your hearts content. Always grab a crystal for carefree rez’ing.
• To make it easier – just have one crystal picked up, and press F on each of the ones on the ground. It will just swap it out and it’s one button press instead of two.
• Another tip: if you’re a banner warrior, summon your banners on top of the rocks so your team doesn’t accidentally miss click when picking up crystals.
• Not sure how well this timing works on Australian connections: If you can’t reach a crystal, dodge as soon as you see the target icon above your head disappear. (I know I often end up double-dodging too soon, so something that indicates “when” would be helpful!)
• I expect this will get patched out: If you have a Guardian with a greatsword equipped, have them use skill #5 to bind the maw tentacle shortly before it dies (but do not hit the next skill for 5) and when it goes through the death animation it’ll spasm some more and pop out a LOT of bonus crystals.

Got any more hints for the Jade Maw bonus fractal? If so, add them to the post as comments below. 😀