How about exposition? Nothing distracts me more than two idiots telling each other what they already know. I think you wrote on this last year, but I don't remember any tips on how to hide it.
What you're describing is the classic "Don and Rob" lecture, in which both characters are merely sock-puppets for the author and exist only to exposit background information, and I think the bit of old bloggerel you're seeking is this one. If not, part of the answer here depends on the effect you're trying to achieve. In comedy, for example, you can get great mileage out of dialog between two flaming idiots who do know exactly the same information and absolutely agree with each other on every point. Alternately, you can make the exposition entertaining by setting it up as a dialog in which one character is really trying to explain something to a third party, but another character is constantly interrupting with non sequiturs and quibbles over utterly unimportant details.
If you're not doing comedy, here are some suggestions for how to disguise a lump of exposition:
1. If both characters know the information: does it really need to be said out loud? Try omitting the exposition completely. Chances are your readers will be able to pick up all they really need to know from context.
2. If the information is deemed essential to the story: do Don and Rob really need to say it? The Don & Rob act is usually a result of overapplying the Show, Not Tell rule, whereas sometimes it's better to just Tell And Get It Over With. If the form of the story doesn't allow for a narrative voice delivering exposition ex cathedra, try slipping in a quote from a fictional reference source, e.g. The Encyclopedia Omniscientia or The Hitchhiker's Guide to the Galaxy. For example, in Rebel Moon, huge chunks of exposition and background were disguised as quotes from an imaginary history book written a century and a half after the events in question.
3. Try wrapping it in a piece of lunchmeat or a glob of mashed potato -- no, wait, that's how I get pills into the dog.
4. Give your characters something to do during the exposition. Keep their hands busy. It breaks up the lump if your narrator has to stop speaking for a moment and fiddle with or react to something.
5. I think the biggest problem with Don & Rob is that when you write two characters discussing a point, whether they're agreeing or arguing, they're both aspects of your writer's voice, so they both fundamentally understand each other. I've gotten good results by putting this sort of exposition into the mouths of characters who not only do not understand each other, they don't even inhabit the same world. For example, here's how I explained the time travel gimmick that was central to a story I sold about 20 years ago. The story begins...
The drugs were taking effect by the time Tyson was wheeled into the projection room, so he had to strain to make sense of Professor Neibelung's words. First the man thanked him, in an oddly evasive way, for 'volunteering' for the experiment. Then the buzzing in Tyson's head let up for a moment and he caught, "--positive by-product of the Berquist Stardrive Disaster was the opening of a region of multi-ply periodic space-time.
"This apparatus," Neibelung continued, as he gently patted the muzzle of the projector, "taps the sensory feeds to your brain and re-routes them through the Berquist Anomaly, where they are reflected off a resonant human nervous system on the other side. In effect, you will experience life as another person in another time." Neibelung walked around the gurney, making sure the straps that held Tyson were good and tight. "You will hear what that person hears, see what he sees, feel what he feels. With careful alignment of the beam, we can select the general place and time. In this test, we will attempt to project you to Renaissance Italy, around 1500 A.D.
"It will be a marvelous time," Neibelung said wistfully. "You may find yourself walking with the greatest men of a millennium." He found a loose strap and snugged it down. "You will, of course, have no free will, nor will you be able to communicate with your host. But on the other hand, always remember that no matter what happens, your body and brain remain safely here. There is absolutely no risk."
Thickly, groggily, Tyson said, "Sounds like bullshit to me."
"It is," Neibelung said with a smile. "If I knew what was going to happen, I'd try it myself." He threw a switch.
...and from that point on, it's pure action to the end of the story.
There, those are some of the standard tools in my kit. Have you found anything that works particularly well for you?