When a Femdom and a cuckold start out its a good idea to put a Cuckold Contract in writing.
This is common practise in many cuckold relationships and makes a lot of sense.
If you do decide to draw up a cuckold contract dont rush it. Take your time. Talk about it first. Write down a general outline of the contract first. Develop the cuckold contract over a few days or weeks before you decide on the final copy. The bulk of the cuckold contract will be about what the Femdom wants, but make sure to add a little for the cuckolds needs also. A long term happy cuckold relationship needs input from both partners.
A good outline in the cuckold contract is to include all the rules and regulations that the cuckold must follow. Also write in detail the expectations of what the cuckold must do. Make sure the cuckold signs all areas of the contract.
Be open to change the cuckold contract over the years as circumstances change. You may need to add changes or remove some stuff that is no longer needed. A cuckold contract should serve more as a guide line and be open to change as the cuckold relationship develops.