There are several ways of playing a wriggle, but the recommended method is known as Helvic.

There are several ways of playing a wriggle, but the recommended method is known as Helvic.
This method allows the partner of the opening 1NT bidder to escape and show any single-suited or two-suited hand. Note that, with a bad, “flat” hand you must choose either to describe it as either a 1-suiter or invent a second suit and treat it as a two-suiter.
With a decent hand, where you expect partner to make 1NT, you put the pressure on the opponents by effectively making the contract 1NT redoubled. If they do not fancy this (perhaps the doubler’s partner has a rotten hand) then they will themselves be likely to concede a penalty when they try to run.

This method allows the partner of the opening 1NT bidder to escape and show any single-suited or two-suited hand. Note that, with a bad, “flat” hand you must choose either to describe it as either a 1-suiter or invent a second suit and treat it as a two-suiter.