
I guess he forgot that
I play the CELLO.
The Big Bang Theory Season 11, Episode 13

This one birthday,
I came home from my CELLO lesson...
The Big Bang Theory Season 1, Episode 16

When I broke up with Penny,
I got back into my CELLO...
The Big Bang Theory Season 4, Episode 3

clearly you've never
seen me play the CELLO.
The Big Bang Theory Season 7, Episode 6

Leonard, you'll play your CELLO.
The Big Bang Theory Season 2, Episode 12