If something is good it gets a thumbs up.
if something is indescribably brilliant - it gets a 'Two Thumbs Up'
But it's simply not good enough to just say the phrase - you must also physically represent the Two Thumbs Up in a strong motion with both hands.
To be used sparingly.
person two 2: 'Yes - Two Thumbs Up' (and dont forget the action of Two Thumbs Up)
person 1: 'kirsten dunst?'
person 2: 'Two Thumbs Up!' (and dont forget the action of Two Thumbs Up)