After you get your cash check with /check <amount>, you can use your check as an item that represents money. You can hide it in a chest somewhere, do a little role-play by giving it to your workers instead of /pay, or just keep it in your inventory.
To get the money in your check, all you have to do is right click somewhere while holding the check in your main hand. Then, you'll get the money and the check will disappear, if the transaction was successful.