give rein to (someone or something)

give rein to (someone or something)

To allow unchecked or unconstrained freedom to something or someone; to completely or freely indulge something or someone. George would make a great businessman if he didn't give rein to his emotions like that. It's a sure sign that this company is failing if they're willing to give rein to the interns like this. You have a nasty habit of giving rein to your drinking.
See also: give, rein