Like a SECRET club?
The Big Bang Theory Season 12, Episode 7
This is the SECRET knock:
The Big Bang Theory Season 1, Episode 16
had been keeping a SECRET
from you and Hank,
Breaking Bad Season 5, Episode 12
Look, why is it so hard
for you to keep one little SECRET?
The Big Bang Theory Season 2, Episode 1
It was killing me
keeping it a SECRET!
The Big Bang Theory Season 11, Episode 8