The end of episode four, season two. Swaim, in a rare moment of brilliance, successfully defends himself against a libel accusation. He manages to outsmart an entire group of lawyers. Then he throws a bag of his shit at them.
The beginning of that same episode also counts.
Dan: I think you just killed Cracked dot com...
Swaim has planted knives everywhere around the world. To demonstrate, he pulls two off his person, one out of his drink, and then reveals that he's even planted on on the secret service agent interviewing him. And they still don't consider him a threat to national security.
Season 1, Episode 3: "Someone called me a FAG."
Season 1, Episode 1: One of the nearly infinite brilliant moments by The Chief: "[Swaim] is one of the best writers we have, but f*ck me with a live fish if he isn't a yammering nutbag"
DOB: I have never heard that expression before.
DOB being Michael-esque in the body switching episode in Season 3.
And only then does he get noticed by Mandy.
From the threesome episode... Michael, pre threesome, suggests making lightsaber sounds every time their dicks touch. He later changes his mind, deciding to go with fart sounds instead. This leads to the following post-threesome exchange.
Michael: Man...you got a weird looking dick.
Dan: That was your dick!
Michael: Really? Looked like yours.
Dan: They were on top of each other.
Michael: So that's why I was making all those fart sounds!