It’s the Russian phrase “Мы сами с усами” usually used in the context of “we weren’t born yesterday” and “they tried to trick is/tell us what to do, but we’ve know how to do it ourselves”.

I cannot find this phrase in the referenced book (googled pdf). Usually it means “we can think/act on our own, please don’t teach us”, but can depend on context, like “we have our reasons”. What it means in the article, I don’t understand. /native speaker

I understood it to be a manliness thing. 'we too can do risky things too', that kind of thing. I'm not Russian though.

It's from a soviet cartoon. There is a cat and a dog. THey live in a vilige and sometimes they fight. SO the meaning is: "You have mustaches and so do I! I'm no worse than you."

This phrase is older than cartoons, it can be found in works of Tolstoy.