CBS/courtesy Everett Cobie Smulders reunited with herHow I Met Your Mothercostar Josh Radnor and series co-creator Craig Thomas on their podcast,How We Made Your Mother Smulders and Radnor revealed that before they filmed sex scenes, she would whisper "extremely inappropriate" things in his ear to set the mood But the duo of actors refused to reveal any of the "filthiest" words she said Cobie Smuldershad an unorthodox method of getting her scene partnerJosh Radnorready for intimate scenes. Smulders, 43, appeared on the May 19 episode of theHow We Made Your Motherpodcast, hosted by Radnor, 50, andHow I Met Your Motherco-creatorCraig Thomas. OnHIMYM, Radnor played uber-romanticTed Mosby, while Smulders played the frequent object of his desires,Robin Scherbatsky. But when the two shared more tender moments on screen, something "extremely inappropriate" was happening behind the scenes. "One of the fun things I like to do with Josh is, Josh and I had quite a few intimate scenes," she explained. "And so I would try to, as much as humanly possible, before we would roll, I would try to whisper something to Josh that was just extremely inappropriate." Cliff Lipson/CBS Photo Archive/Getty Smulders jokingly explained that in acting there's something called "the moment before," which involves visualizing what you were doing just before the scene begins. She was being "a good scene partner" when she would whisper to Radnor whatever sexual act Robin and Ted were just doing since a lot of the scenes, Radnor explained, were "post coital." "Because I'm a giving actor, I feel like I'm an amazing scene partner, and I'm just thinking about the other person and making sure that they're comfortable, making sure that there's a connection there," Smulders said with a laugh. "I would just sort of set us up before we actually started the scene in our speaking roles just with, 'This is what just transpired between us,' " she said. In the video of the podcast, Radnor's face was bright red, and Smulders said that in those moments after she whispered to him on set, the same thing would happen. Thomas, 49, asked if Smulders could give an "appropriately worded example." Smulders and Radnor both said they couldn't, and she offered, "Just think of the worst possible thing and that's really what it was." Radnor said that his costarNeil Patrick Harris, who played Barney Stinson, would also whisper things to him. "Neil is disgusting. Like, Neil has a real ability to be gross and work blue," he said. But, "He is nothing compared to the depravity that Cobie Smolders laid out." Thomas said he "never knew" about this. Radnor said Smulders was so good at timing it that she would "stick the landing" just before the cameras rolled. "I couldn't speak," he said. "They're fond memories. I was immobilized by Cobie's vision." He joked that if "acting stops," she should try writing "the filthiest romance novels" because she has "a real talent for spinning the dirtiest webs of narrative" that were "shocking" and still "deligthful." Monty Brinton/CBS/Getty Never miss a story — sign up forPEOPLE's free daily newsletterto stay up-to-date on the best of what PEOPLE has to offer, from celebrity news to compelling human interest stories. Thomas again asked for more details about what she would whisper, but Smulders said, "This is between Josh and I ... This is a moment in time, and only Josh and I know exactly what was said and the context of what was said and how it was delivered." Radnor added, "Your imagination is free to wander." Radnor added that he was "extremely breakable" — meaning that he often started laughing during scenes when he shouldn't have — and that on the blooper reels from the show, he's probably laughing because of Smulders' whispers. Smulders said she could often lose it with laughter during a scene, too. "You're telling yourself, don't laugh. And then you enter into a phase where you're like, 'I'm so unprofessional,' and you're sort of self-shaming. Like, I'm the youngest one here, and they all know what they're doing, and I can't not laugh." She added thatJason Segel, who played Marshall Eriksen, was usually the one who got her to laugh. Read the original article onPeople