I'm very confused as to how this works, because I can't find info on it anywhere...

When using the coupon does it use the characters EXP you use it on?

Or can you pick what character EXP is going to be transferred to the character using the coupon?

Someone please explain it to me :( I got a few days left to use it.

I want to transfer the exp on my Sage to another character (in case that helps with explaining ^^'')

You swap the EXP between the character you are on and the one you select.

And to make it clear: The coupons don't transfer the EXP from one char to an other, they exchange them between 2 chars.
eg. Char A is lvl 62 and Char B is lvl 59.
After you used the coupon Char A is lvl 59 and Char B is 62.

Oof alright, i thought it simply transferred exp... but i guess that means i can just bin it XD