Ticks are the little annoying personal movements they make.
Most of the girls, ok, all, are guilty of wiggling their hands and fingers too much. But there's more.
Che... Walking around. Stop it.
Mason... The swaggy knee switching dance move.
Bupsi... Swinging her left arm.
4th impact... Rotating almost 90 degrees perpendicular to the ground with arms pointing in various directions.
Max... He looks like he's inviting hugs.
Seann... One eyebrow is angled more extreme than the other when he twitches them.
Alien uncovered... Nothing is consistent hah.
Anton... Open wide, say ahhhhh. O.O
Monica... Piano fingers overworking.
Reggie n Bollie... Gyrating...
Lauren... Like Che she walks around the stage like she's doing the classic knight on a chessboard puzzle.

Did I miss any?

Mason has a very awkward "I fought in 'nam" right eye wink/twitch.

Seann does this 'arm stretched towards the camera' thing, while adopting an expression that's a cross between 'beseeching', 'pained' and 'tabloid sad-face'.

Anton looks permanently startled. He reminds me of this smilie ---------->

4th Impact whip their hair...a lot, which looks fine in uptempo numbers, but will look decidedly odd when they're singing ballads.

Wrong year I know but Fleur seemed to have a nervous wink/twitch going on when she sang Uptown Funk in the final!

Anton's huge gob and crazy, stare-y eyes.

Down memory lane...Louis saying 'You look like a little...'

I agree...