He's HOLDING the phone to his left ear.
Ears do not cross hemispheres.
The Big Bang Theory Season 2, Episode 15
I'm HOLDING my breath
until your hair grows back."
The Big Bang Theory Season 8, Episode 1
And you're HOLDING her head
while she's puking...
The Big Bang Theory Season 1, Episode 12
So how you HOLDING up?
Breaking Bad Season 3, Episode 13
How's Bernadette HOLDING up?
The Big Bang Theory Season 11, Episode 16