That's an involuntary TWINKLE.
The Big Bang Theory Season 5, Episode 21
there it is,
there's that TWINKLE.
The Big Bang Theory Season 5, Episode 21
Hey, Ma, TWINKLE, TWINKLE,
your little star is home!
The Big Bang Theory Season 6, Episode 4
Hey, Ma, TWINKLE, TWINKLE,
your little star is home!
The Big Bang Theory Season 6, Episode 4
I see that TWINKLE in your eye
The Big Bang Theory Season 5, Episode 21