irse de picos pardos

The original meaning of "go to a brothel" stems from the days of Charles III of Spain, when prostitutes had to wear a brown dress cut in such a way that they resembled beaks.

irse de picos pardos (first-person singular present me voy de picos pardos, first-person singular preterite me fui de picos pardos, past participle ido de picos pardos)

1. (idiomatic) to go out on a bender; paint the town red
2. (archaic, idiomatic) to go out whoring

• “irse alguien a, o de picos pardos”, in Diccionario de la lengua española, Vigésima tercera edición, Real Academia Española, 2014