How do you use the shining charm in masuda method?

I don't have one yet but I'm aiming for one and I have a japanese ditto.

Well once you have it it just automatically ups your chances, so you just do the Masuda Method once you have it and it just ups your chances of finding a shiny :)

So you don't have to give it to a pokemon to hold?

No it is like a key item.

If you had to equip it to a pokemon it would be as simple as putting it on the first one in your party or giving it to whichever pokemon you are trying to breed into a shiny.

I see,thanks! :)

does anyone have a shiny charm there willing to trade for

I don't think it can be traded karrmakazzi... It's a key item so can't be assigned to a Pokemon, unless hacked you can't trade it..