Filmed in North Wales in locations including Snowdonia National Park, the market town of Ruthin and port of Holyhead, Two Men And A Tent featured the pair abseiling down and sleeping overnight on the side of a cliff.
"I didn't sleep a wink" admitted Manford, who was also seen ascending Mount Snowdon with Flintoff and a film crew last month, posting several photos of the trip on his Instagram page.
He told listeners to his Absolute Radio show that former cricketer Andrew "Freddie" Flintoff "had a lie-in" while they were secured to the ledge. "He loved it!"
Yet there were "noises from birds that you've never heard in your life" he continued. "Terrifying birds. You've got to lie on your back because you're harnessed in, so you can't get your sleeping bag over your shoulders.
"So it's freezing. Loud. These birds called like shag and chuff, which were funny at one o'clock in the afternoon and are not funny now. Not laughing at the shag or the chuffs, let me tell you. And also it was dark for about two hours. One o'clock dark, four o'clock light again. Unbelievable.
"Anyway, it was an experience ... which I would never do again or recommend to a friend. But I enjoyed it."
Two Men And A Tent is directed by Marcus Liversedge (British As Folk, Almost Royal) for South Shore (Home Alone With Joel Dommett), who have made several shows with Flintoff, including the BBC One documentaries Freddie Flintoff: Living With Bulimia in which he opened up about suffering with the eating disorder and currently, Freddie Flintoff's Field Of Dreams, in which the ex-pro assembles a cricket team made up of underprivileged teens who had never played the game before.
Both Manchester City fans, Flintoff guested on ITV's short-running entertainment series The Nightly Show in 2017 when Manford was hosting and the duo were both booked as guests on All Round To Mrs. Brown's in 2018 (pictured top). Later, Manford appeared on a 2012 episode of Sky's panel show A League of Their Own, which featured the late cricketing legend Shane Warne bowling balls at Manford's penis while he was strapped to a revolving wheel.
Manford told his Absolute listeners that he'd known Flintoff "a long time. But I don't know him well. I see him at the gym, we have the odd coffee together and a little chat."
So when he got the phonecall to shoot Two Men And A Tent, two weeks before filming and having just been camping in North Wales with his family, "I presume someone must have dropped out" he speculated.
"In my head I'm thinking who's supposed to be doing this? It's got to be Paddy [McGuinness], Jamie [Redknapp] or Romesh [Ranganathan]!"