Double Trinketing used to be something Mages were notorious for way back in the days. We were able to activate two damage trinkets at the same time, while also using Arcane Power and Presence of Mind to really take down someone with really high numbers.
You would be able to activate the [Talisman of Euphemeral Power] and [Zandalarian Hero Charm] at the same time and receive both bonuses to wreak havoc. That however was nerfed by Patch 1.10. Now when you activate a trinket, it will trigger a cooldown on all similar trinkets that is equal to the duration of the buff of the trinket you just activated.
Double Trinketing was gone, non-Casters rejoiced, and Casters were sad. Mages however still have a way to double trinket.
To do this, you will need the Mage class trinket from SSC, [Serpent-Coil Braid] and a damage trinket which lets you activate to give you a spell damage buff. For my example I’ll use the [Icon of the Silver Crescent].
The Serpent-Coil Braid will grant you 225 Spell Damage for 15 seconds everytime you consume a Mana Gem. The Icon can be activated to increase your spell damge by 155 Spell Damage for 20 seconds, and is on a 2 minute cooldown. Since Mana Gems also have a 2 minute cooldown, both trinkets can be used together everytime.
Normally if you use a Mana Gem to activate the Serpent-Coil, it will trigger a 15 second cooldown on all other spell damage trinkets. But if you activate a spell damage trinket, it WON’T trigger a cooldown on your Serpent-Coil. Therefore if you activate a spell damage trinket and then consume a Mana Gem, you will be granted the spell damage bonus from both trinkets at the same time.
Here is a macro that you can use to help you to do this:
#showtooltip Icon of the Silver Crescent
/use Icon of the Silver Crescent
/use Mana Emerald
You can modify this macro depending on what trinket you are using, or add spells to it.
The exact macro that I use while raiding is this:
#showtooltip Icy Veins
/cast Icy Veins
/use Hex Shrunken Head
/use Mana Agate
/use Mana Jade
/use Mana Citrine
/use Mana Ruby
/use Mana Emerald
/cast Summon Water Elemental
This macro allows me to activate both trinkets, cast Icy Veins, and summon my Water Elemental all at the same time. It will use the lowest Mana Gem in your inventory everytime you use the macro. The reason I have all Mana Gems is for long fights where you are able to use Mana Gems more than three times. For the Illidan fight, I actually use two Mana Gems in Phase 1, re-conjure them at the beginning of Phase 2, then consume all five gems by the time Illidan dies (15+ minute fight).
Just be sure to remember that you are NOT at full mana when you activate your macro. You can’t consume a Mana Gem if your mana is full. For PvE I would activate my macro after getting five Winter’s Chill debuff on the target. In PvP, I would cast Ice Barrier on myself before using the macro, although I normally don’t use this macro in PvP. I tend to save my Mana Gem cooldowns for Health Stone usage.
So if your lucky enough to get a [Serpent-Coil Braid], make sure you use it to its fullest potential.