draw in the reins

A long narrow leather strap attached to each end of the bit of a bridle and used by a rider or driver to control a horse or other animal. Often used in the plural.

A means of restraint, check, or guidance.

A means or an instrument by which power is exercised. Often used in the plural: the reins of government.

To check or hold back by or as if by the use of reins. Often with in, back, or up.

To restrain or control.