The 45-year-old comedian and TV presenter joined the ITV panel to discuss his new book, Beyond the Sky: You and the Universe, which answers a range of questions about space.
Dara explained that the book is aimed at eight-year-olds and also features fun cartoons and facts.
Lisa Riley, 41, appeared to voice what all her co-stars were really thinking, however, when she asked a rather rude question about how astronauts live.
“I want to know how they do the poo poo,” she said, as Andrea McLean, 48, Stacey Solomon, 28, and Gloria Hunniford, 77, all chipped in to share their support for her query.
Dara shook his head in disbelief, saying reluctantly: “They have a suction thing and it’s uncomfortable and it used to be a bag and it was awful.”
“Sorry, you said suction thing,” Loose Women host Andrea interjected.
“There’s a special seat that they sit on and theres a hole…” he tailed off as Andrea exclaimed: “It sucks your poo out?”
“No, no, no,” he insisted, struggling to explain the awkward matter. “You still do what you do but very near to where you do what you do, there’s a thing that draws it, that makes sure it -“
“What happens to the wee?” Andrea chipped in, as Dara tried to clarify: “The poo gets bagged up and shot out of the window, essentially, and burned up. Then the wee gets recycled back into drinking water.”
He later joked that the eight-year-olds at his children’s’ school weren’t even as curious about the lavatorial side of things as the Loose Women were.
Andrea admitted that she struggled to get enthusiastic about space science, but that Dara’s explanations made it more accessible to her, laughing: “I’m clearly going to have to read a book aimed at eight-year-olds and that will get me in.”
Dara made a sly dig at Andrea and the rest of the Loose Women’s IQs, quipping: “I thought that might be pitching it too high but then I saw how excited you were about the poo discussion earlier and so I think this book has found its home!”
Loose Women airs weekdays at 12.30pm on ITV.