You can check your membership benefits and when you see being a friend for free click on it and it will show you what days they can go in for free. They also have other options like 50% off ticket for a friend or bring a friend for 10 dollars. If you end up redeeming the free entry for a friend you just go straight to the entrance and let the turnstile people know that you want to use that benefit and they will simply scan your pass
Anytime is a good time to bring a friend...
Thanks! Your answer is awaiting moderation.