He does this HYSTERICAL impersonation
of Stephen Hawking having phone sex.
The Big Bang Theory Season 2, Episode 11
Yeah, it's HYSTERICAL.
The Big Bang Theory Season 4, Episode 22
That's HYSTERICAL.
The Big Bang Theory Season 7, Episode 15
I think I'm HYSTERICAL.
The Big Bang Theory Season 7, Episode 12
I also have a HYSTERICAL bit
planned for later
The Big Bang Theory Season 5, Episode 24