Educated language vs Slang

Recently, a "professor" of Argentinian Spanish (?) was telling people in Instagram that in that language "coger" means to have sex, and "pillar", means to urinate, and advised her students not to say  "terminar" because it means to have an orgasm. The lesson ended there, thank God, because otherwise, we would have learnt that it is impossible to use plain run-of-the-mill vocabulary in Buenos Aires without offending someone. Of course, the same problem we might encounter in Peru, Chile, Mexico, or Spain, and that´s why I promote the study of cultured, educated, language, in any language. An educated Bolivian will always understand an educated Mexican. So, please, stay away from "colloquial" dialects and stick to mainstream language which will always keep you in good stead.