I am a fan of metaposing for when things need to be made obvious or explicit, or for light comedic value.
I mentioned somewhere else that I was at one point known in my group for always metapose-remarking that my characters were jerks.
e.g.
Tony watches as John pats around for his contact lens. Spotting it, he shifts his foot and crushes it quietly. "Gosh, John, I can't seem to see it anywhere!" He's such a dick.
I'll also do things like:
Tony shakes his head. "I swear I didn't know anything about this!" But he can't contend with the fact that he's a horrible liar.
The former is to highlight that I know my character is a dick; authorial awareness is a good thing. The latter is to let people know I'm okay with them calling him on a lie. If I don't do that, I'll generally ask for rolls or contend the calling out (and often his lying skills will find their way into the pose, e.g. *[...] He hods his up genuinely; if he's lying, there's no obvious outside indication."
In either case, if the game is with dice, I'll be more than happy to roll them.