This is from Series 2 of the show.
Basically, David Mitchell plays a film director who has an obsession with 'realism' in his films, and is interviewed about this by Robert Webb. One of his films is called 'The Man Who Has A Cough And It's Just A Cough And He's Fine', which they show a clip of (Cue Robert Webb dressed as a stereotypical middle class 1900's Brit coughing into a handkerchief. Yeah.) Then they show another clip from his film 'The Gathering People', where an actor I don't know the name of battles a 'tease sneeze' in the most comical way imaginable. Why am I telling you this? The video's right there, WATCH IT!
Rob's coughing starts at 1:30 (And a beautiful shot of him with watery eyes and a pale face at 1:53...), then the sneeze teasing starts at 3:35 and then the sneeze eventually happens at 4:17. It's a comedy show, so it's all very over the top and silly, but I got a kick from this whole thing and I'm posting it SO THERE.