Cruise passengers given warning on ‘risky’ item of clothing they don’t want to be wearing

Ah, the weird and wonderful world of cruises.

Quite often I find my mind wandering as I imagine what they're really like.

Would I be bored? Would I feel seasick?

Luckily for you, we've got pretty much all bases covered when it comes to sea-based odysseys, whether that's costs, how to get the best deals or buffet etiquette.

It seems there's all kinds of rules and codes on board, and it's always better to be in the know.

Today, we're going to be talking about your wardrobe choices.

One guy took to Reddit to share why his shirt caused such a stir at sea.

He posted: "TIL [today I learned] about the upside down pineapple. And now it makes sense why a couple on a Carnival cruise were so seemingly enamoured with my pineapple print Hawaiian shirt!"

Cruise Hive states: "On a cruise ship, the secret symbol of an upside-down pineapple is regularly used as a code for swinging or 'wife-swapping'.

"In most cases, an illustrated and upside-down pineapple is fixed to the cabin door of a guest interested in swinging and partner swapping."

Ah, gotcha.

There's more, of course.

You may want to refrain from wearing a shirt featuring your favourite fruit. (Getty Stock Image)

"Attaching an upside-down pineapple to the cabin door is the most obvious way people advertise their openness to swinging, but some cruise and resort guests use the upside-down pineapple symbol more subtly.

"Instead of attaching an upside-down pineapple to their cabin door, they might wear an upside-down pineapple pin or simply wear a Hawaiian shirt with a pineapple print."

This checks out, as a couple that took to TikTok to share their experience of being on a 'spicy cruise' - where they swing with other couples - they added that they 'have some pineapple stuff to put around [their] room.'

On the unsuspecting anonymous man's Reddit thread, people shared their own experiences.

One person wrote: "I usually like to walk the decks for exercise. It's fun to look for the pineapples on the doors."

Another said: "I have a significant amount of tropical shirts (50+). The number was higher until I had a cruise where a few people were uncomfortably friendly to my wife and I. Someone finally let me know that wearing shirts with Pineapples attract that type of attention and I should retire those shirts if we weren't into the lifestyle. So my shirt collection went down by about half a dozen shirts after that cruise."

A third chimed: "Dude! That is exactly what happened to me! Read more about the lifestyle and was blown away about the pineapple thing and how long it's been around. Tempted to wear those shirts and troll people with bizarre answers to their attention in future. Won't really, but tempting."

The more you know, eh?