Coughlan tells PEOPLE about the challenges of playing a character that “doesn’t know what sex is” in season 3 of ‘Bridgerton’

Nicola Coughlan’s Bridgerton character, Penelope Featherington, is shedding her innocence in season 3.

The 37-year-old actress opens up to PEOPLE about the challenges of playing a character that “doesn’t know what sex is.”

“Even when we had the first kiss, they had to say to me, ‘You can’t seem like you kissed someone before,’ which is like, okay, yeah, because even it’s hand placement, since it looks a little too mature and you’re like, okay, pull it back, she’s never done this,” the actress says of her intimate scenes with on-screen love Luke Newton.

Newton — who plays Colin Bridgerton on the hit Netflix series — also tells PEOPLE that “ultimately, the goal was for it to seem really authentic to those two characters.”

“We just wanted to honor that because people have a lot of love for their relationship, and we wanted to keep it really true to that,” the actor, 31, shares. “So we would have discussions about how their first encounter would be and what the intimacy would be like, and if it would be, and we talked to the intimacy coordinator of even the intensity of the scene and if it was quite…how gentle they would be with each other when it’s the start of something and where we can take it from there.”

Coughlan admits that keeping Colin and Penelope’s friends-to-love romance authentic was important to both her and Newton.

“The intimacy stuff feels very real,” Coughlan says. “It feels very grounded in two people that are not trying to sort of, that they’re awkward in front of one another, this and that, and all of a sudden they become like Lotharios in the bedroom and whatever, they get to be intimate together in a very real and beautiful way, and I think that’s what makes it so affecting.”

“In those intimate moments, they find moments to laugh and you see them figuring it out and doing it together, and I love it,” she adds.