Idiom search

I am looking for an idiom for convincing someone through implicit threat without actually meaning to carry it out. There are words that describe a similar concept with different shades of color such as "blackmail", "brinksmanship" and "bluffing" but I am trying to remember a crisp idiom that hits the nail on its head. I think it starts with a verb.

For example, a customer may ask for paring down an already minimal specification to reduce the cost while his real intent is to bargain the price down.