This phrase is used in a comedic or sarcastic manner to refer to a situation when everything is going wrong. It literally translates to 'the only thing left is for a dog to pee on you'.
Examples
- Spanish: Perdí mi trabajo, se rompió mi coche y mi novia me dejó. Sólo falta que te orine un perro.
- English: I lost my job, my car broke down, and my girlfriend left me. The only thing left is for a dog to pee on me.