What does free mustache rides mean?

"Free mustache rides" is a humorous phrase often used to suggest a playful or cheeky offer, implying that someone is inviting others to take a ride on their mustache, which can be interpreted as a double entendre related to intimacy or flirtation. It originated as a lighthearted joke and is commonly found on novelty t-shirts or signs. The phrase plays on the juxtaposition of something seemingly innocent with a more suggestive undertone. Overall, it’s meant to evoke laughter and amusement rather than a literal offer.