"Koo" from Koothrappali
and "PER" from CooPER.
The Big Bang Theory Season 9, Episode 12
As PER your suggestion,
we're hanging out.
The Big Bang Theory Season 4, Episode 5
Really more to organize,
you're not actually dirty, PER se.
The Big Bang Theory Season 1, Episode 2
...between the number of chirps PER
minute and the ambient temPERature.
The Big Bang Theory Season 3, Episode 2
The average cork speed
is 25 miles PER hour.
The Big Bang Theory Season 10, Episode 6