Use this phrase in casual environments where being laid-back is appropriate. The picnic is a chance to let it all hang out with friends.
Pro Tip 2/3
Not for Formality
Avoid this phrase in formal settings like business meetings or official ceremonies. It's a casual get-together, not a banquet, so you can let it all hang out.
Pro Tip 3/3
Avoid Misinterpretation
Some might misunderstand this phrase as being reckless or irresponsible. He's not careless, just likes to let it all hang out at times.