A couple in the United States have gone viral after revealing how they hilariously sent off the wrong, ahem, signal while on holidays.
TikTok user @linjeanw shared photos of her and her husband on holiday, revealing they thought it had been "cute" to wear matching swimsuits.
"Wearing matching pineapple swimsuits with my husband on vacation because I thought it was cute," she captioned the video, which showed the couple wearing fruit-emblazoned swimsuits during their holiday.
But they hadn't known that pineapples – in particular upside-down pineapples, which @linejeanw's bikini had featured – was the international symbol for couples who swing.
"People were a little extra nice," she added.
@linjeanw's video has since been viewed more than 2.8 million times, with people losing it over the couple's innocent mistake.
"Y'all walking around wondering why you are so popular," one person wrote.
"Gonna tell my wife to wear pineapples on vacation," another said.
"I just realised I made my boyfriend wear a pineapple shirt and I wore a pineapple dress while on vacation two years ago," one also commented.
Others said they couldn't believe pineapples were used as a symbol for swinging, arguing it wasn't "obscure" enough to be used for it.
"Pineapple stuff is too cute," one commented.
"Let's take pineapples back! Swingers can use something else," another person joked.
What does an upside-down pineapple mean?
Pineapples have long symbolised hospitality and, according to Urban Dictionary, are used by swingers to show when a party is happening.
"A pineapple is placed on a porch or mail box by swingers to signify that a swing party is going on," Urban Dictionary's entry reads.
Urban Dictionary also claims upside-down pineapples on clothing are also used to signal when someone is looking for a swingers party.
This claim appears to be backed up by blogs and anecdotal evidence on Reddit, with it reportedly used often on cruises to signal when a couple is down for some wife-swapping fun.