You don't need to go shouting it, but if someone starts talking politics at you, fucking own it. Some coworker is like "trump sucks", say "yeah I know, I'm a communist". Your grandpa says "trump rules", say "no he sucks ass, I'm a communist". You're on a date and they ask who you're voting for? Say "I'm a communist". Cashier asks would you like change? "Yes, I am a communist".
Be open about your politics and lay claim to the title. Be a communist.
"Tell you what. If you can get 100 words down, on paper, without using the internet, explaining how "China Bad" and "Stalin Bad" are effective retorts that disprove dialectical materialism and render the entire concept of Communism null and void, then I will stop being a Communist."