On Thursday's "Jimmy Kimmel Live," Tatum shared the time that he and Hill, 28, went for a late-night, X-rated dip while in Miami, where they were filming "21 Jump Street."
"We decided to jump in the ocean -- naked. It was nighttime, thank God," Tatum told Kimmel.
The actor, 31, continued on about the crazy details of the night.
"There's Jerry's Deli right on the corner and [Jonah] decides he wants to go in and all he's got is his T-shirt and his underwear on and he's like, 'I'm going in to get something to eat!' and I'm like, 'No!' So I stopped him and [took] him back to the car."
"Now he's nicknamed 'Baby Jonah' because I had to dress him like a mom. I'm like, 'No, no. Bad Jonah. No. Butt up, butt up. OK."
The indecent swimmers aren't the only 21 Jump Street stars that enjoyed themselves during the off-hours of filming.
"There were jars of moonshine, and everybody had their hands in them," their co-star Jake Johnson laughed to Us Weekly at the film's premiere in Hollywood Tuesday. "It was brutal!"
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