See "por la patilla" ("por la cara", "por la cara bonita", without deserving it, without remuneration" ), verbs/ha, verbs/fact, patilla. See also "go for the sideburn", "go for the paw down"
HE HAS DONE IT FOR THE PIN in Spain: do something for free. See BY PIN . In urban language GO BY THE PIN is to, lose control of the sphincters.