Marmoset monkeys should be given boundaries and disciplining them should start early. It is important to set a consistent routine and be in charge of interactions with the monkey by always reinforcing positive behavior and avoiding reinforcing bad behavior.
Most importantly, as with all primates, remind them that you are in charge and hold the authority. Ensure to provide them with appropriate toys and treats as rewards when they behave well. If misbehaving does occur, try to remain calm, be assertive, and give them a firm verbal warning and if necessary, a time out.
When it comes to disciplining a marmoset monkey, patience and consistency are key.