echar una cana al aire

Literally, “toss a grey hair into the air”.

echar una cana al aire (first-person singular present echo una cana al aire, first-person singular preterite eché una cana al aire, past participle echado una cana al aire)

1. (idiomatic) to let one's hair down

• “echar alguien una cana al aire”, in Diccionario de la lengua española [Dictionary of the Spanish Language] (in Spanish), online version 23.7, Royal Spanish Academy [Spanish: Real Academia Española], 2023 November 28