You could do something like this.
Code:
/use [btn:1] Cloak1
/equip [btn:2] Cloak2
/use will equip the first cloak if it's not already equipped and you click the macro again to activate the use function. Then you right-click the macro to re-equip the second cloak.
You will need to change
Cloak1 and
Cloak2 to the respective item names.
You'll have to have a custom addon made to have a solution that remembers your previous cloak, though
/equip does accept bag and slot IDs.
For example, if you always keep your cloak in the top-left slot of bag 4 (count 4 bags from the right, not including backpack), this will look like the following (with macro conditional added).
Notes: BagIDs count right-to-left with backpack at bag zero, SlotIDs count left-to-right and top-to-bottom starting at one at the top left. Bags with two slots on the top aren't skipping slots, that's just how the UI displays bags that don't have a slot count divisible by 4.