Manny Jacinto says his 'I Want You Back' costars Jenny Slate and Gina Rodriguez improvised part of their threesome scene

• Warning: This article contains spoilers for Prime Video's "I Want You Back."
• Manny Jacinto said Jenny Slate and Gina Rodriguez improvised the movie's threesome scene.

When Manny Jacinto, Jenny Slate, and Gina Rodriguez teamed up to shoot the threesome scene in Jason Orley's romantic comedy "I Want You Back," they committed to making it feel as authentic as possible.

"The thing with a threesome scene is that — not that I know from personal experience — but it can get a little raunchy in a sense," Jacinto, 34, told Insider ahead of the movie's Friday release. "We didn't want that. We wanted something that was grounded."

Jacinto's Logan, an elementary-school drama teacher, is the only party that has any desire to be in the bedroom. His girlfriend Anna (Rodriguez) grows territorial at the mere idea of sharing him, and Emma (Slate) feigns sexual prowess for the sole purpose of breaking them up.

To capture the air of discomfort in the room, Jacinto said the actors intentionally bypassed any and all things sexy, instead prioritizing a "sweet" and "purposeful" depiction of a ménage à trois gone wrong.

The actors improvised to make the situation more authentic

On the night of the prescheduled threesome, Logan does his best to set the mood. He pours red wine. He lights candles. He plays romantic music. Though well-intentioned, the romantic gestures do little to salvage the situation.

In order to capture the unease and tap into their characters' psyches, the actors improvised the scene's opening moments, Jacinto recalled. Playing off of each other in an organic way made Logan, Anna, and Emma seem more like real people "in a situation that they've never been in before," he told Insider.

The characters all handle the interaction differently — Logan tries to balance his attention between the women, Emma tries to push the threesome along, and Anna grasps for excuses to stall. Since Anna is desperate to put off the sexual encounter, she jumps at Emma's suggestion that they should dance for Logan.

And, according to Jacinto, Rodriguez and Slate took full creative liberty during the dancing sequence, striking gold with their spur-of-the-moment routine.

"That was all improvised. They should get like a dance or choreography credit for what they did," he joked, adding, "A lot of it was improvised and felt on the day to see what worked."

The scene factored into Jacinto's decision to join the cast

When the Isaac Aptaker and Elizabeth Berger-penned script landed in Jacinto's lap, the failed threesome immediately grabbed the actor's attention.

"That definitely stood out when I first read it," the "Good Place" actor told Insider. "I was like, 'This is either going to be really awkward or really great.' Turns out, it was both."

Rodriguez and Slate were already attached to the project by the time Jacinto signed on as Logan. While he didn't know either actress personally at the time, he said he had "only heard amazing things" from his friends who had worked with them in the past.

"That really solidified me saying yes to the project," Jacinto told Insider.

"I Want You Back" is now available to stream on Prime Video.