keep on a tight leash

keep somebody on a tight leash

also keep somebody on a short leash
to allow someone very little freedom to do what they want He doesn't go out with the guys much now that his girlfriend is around to keep him on a tight leash.
Usage notes: sometimes used with have: The police will have a tight leash on all the suspects until the trial.
Etymology: based on the literal meaning of leash (a length of rope or leather used to prevent a dog or other animal from getting away)
See also: keep, leash, tight