They’re sticking it where the sun-ray don’t shine.

While remoras are known to be rather clingy, some are getting too close for comfort by diving into manta rays’ backsides, per a scientific probe in the journal Ecology and Evolution.

“These fish are heading up right into some manta ray rear-ends,” lead author Emily Yeager, a marine researcher at the University of Miami, exclaimed on the Canadian Broadcasting Corporation radio show “As It Happens.”

Known as “cloacal diving,” the “uncomfortable” practice involves flitting in and out of a larger critter’s cloaca — the multipurpose orifice used for both pooping and reproduction.

This seems like a revolting departure for these so-called benign suckerfish, which latch onto marine mammals such as whales and sharks, cleaning parasites and dead skin off the host in exchange for food, protection and free transport.

As it turns out, this so-called symbiotic relationship could be more parasitic than once thought.

While the intrusive behavior had been observed between remoras and whale sharks, this was the first time they’d documented these hitch-hikers of the sea infiltrating manta rays’ rears.

Over the span of 15 years, the researchers observed them practicing ray-related cloacal diving seven times in different parts of the ocean — although Yeager believes this occurs much more frequently.

“We think this is an under-reported phenomena because, oftentimes, you just see the very tip of the tail poking out from the backside of the manta ray,” the scientist said. “They’re really wedging themselves into that area.”

While the catalyst for this anal-seeking behavior is unclear, the researchers believed it could be a fear response based on one of the clips.

In it, a remora was captured vanishing into a manta ray’s bum after getting startled by a researcher.

This prompted the host to shutter its cloaca, before swimming away with the aquatic butt-plug lodged inside.

However, others believe that the remora could have a far more revolting motivation.

Brooke Flammang, a biology professor at the New Jersey Institute of Technology, told the CBC that these rear-moras could be practicing, “coprophagy — “Latin for eating poop” — and that the fish in the footage could’ve been trying to beat rivals to the prime chomping grounds.

“They can be territorial about sharing space on the same host,” said Flammang, who wasn’t “totally surprised” that these suckerfish like to forage in the fanny.

As she pointed out, “remoras are just that weird.”

While its difficult to know what the rays make of these aquatic colonoscopies, Yeager suspects that they’re not too keen on them.

In fact, the behavior could even impact the mantas’ cloacal function over time, she theorizes.

“If they do that in the cloaca opening, which is likely much more sensitive than other parts of the manta ray’s body, it could cause really severe damage and influence reproduction and also excretion of waste over time,” Yeager said.

In accordance, the researcher believes that this so-called relationship isn’t totally mutual, but rather exists “on a spectrum, just like any relationship in your life.”