Im pretty sure the credit coupon symbol is detailing similar to his handcuffs but using that to be like a wrist tattoo with the diamond on his inner wrist
Also if you guys havent guessed I was thinking about this for awhile. I know its like a silly fun thing but I definitely love funny symbolism stuff where only he understands it at first and then maybe others will understand with time
we don't talk about how fighting a good opponent gets him a little excited