"Dar pitaco" means opining about something. Literally it can be translated like "to give an opinion; to show your point". But it's necessary to emphasize that it isn't a synonym of opinion, it's more like 'to butt in' a conversation, which means interfering in a conversation without being asked.

"Pitaco" means a comment, an opinion, usually an unfounded or unwanted one. You will often find the expression "dar pitaco". It is rather informal though. If you hear something like "lá vem ele dar pitaco outra vez", that is a very nosy person. :)

Hi gabi! Eu nunca escutei essa palavra aqui no Brasil, por isso procurei no dicionário e pitaco significa: opniao desnecessária sobre algo que desconhece.