button
as bright as a button: seebright.
button your lip remain silent. informal
on the button
1 punctually.
2 exactly right. informal, chiefly US
press the button initiate an action or train of events. informal
☞ During the Cold War period, this expression was often used with reference to the possible action of the US or Soviet presidents in starting a nuclear war.
press the panic button: seepanic.
push (or press) someone's buttons be successful in arousing or provoking a reaction in someone. informal