grab (someone) by the short hairs

Переводы
держать (кого-то) за слабое место
The manager knew exactly how to grab him by the short hairs to get what he wanted.
Менеджер знал, как держать его за слабое место, чтобы получить желаемое.
Определения
To have someone in a vulnerable or powerless position, often by having control over something important to them or by having leverage that forces them to comply with demands.