
...the one where the FROG has its tongue
stuck to the underside of an airplane.
The Big Bang Theory Season 6, Episode 19

Or you're just
a tall, annoying FROG.
The Big Bang Theory Season 7, Episode 16

Like the FROG who's put
in a pot of water
The Big Bang Theory Season 7, Episode 16

Well, I'm sorry
I'm not a FROG.
The Big Bang Theory Season 12, Episode 17

From now on, "FROG" is me, "sandwich"
means you, and "lemon" means rocket.
The Big Bang Theory Season 6, Episode 3