el burro delante, pa que no se espante
(the donkey goes first, so it doesn't get scared) •
In Spanish, it is usually considered impolite to refer to oneself while listing the members of some group before every other person has been mentioned. This expression is used to make someone aware of his misplacement of the first-person pronoun in an enumeration that includes more people.
"¿Y quiénes fuisteis al cine?" "Fuimos yo, Joan y Pablo." "El burro delante, pa que no se espante."
"And who went to the cinema?" "Me, Joan and Pablo." "The donkey goes in front, so it doesn't get scared."