Let your hair down
Meaning: to relax and enjoy yourself, to be relaxed and informal with other people
Example: She is always so formal. She never lets her hair down.
Выучи грамотный разговорный английский до уверенного владения всего за 9 месяцев по системе естественного усвоения иностранных языков. Жми!
Example: She is always so formal. She never lets her hair down.