When talking backwards to BoJack, Todd says, "I'm talking backwards. Aaron Paul is dead."
At the start of the drug party they riff on "Dr. Hu," "Dr. Who," "Who's Dr. Hu," "I don't know," "Third base!" In the 1930s the comedy team Abbott and Costello did a routine about baseball players with odd names. The basemen were named "Who," "What," and "I don't know." The dialogue went: "Who's on first?" "Yes." "What's the name of the guy on first base?" "No, What's the name of the guy on second." "I don't know." "He's on third base."
This contains rare visual references to actual animals: BoJack's desktop background contains a bearskin rug, and while tripping BoJack sees an actual horse in his bathroom door.
In the scene where Todd is talking backwards, this could be a nod towards Twin Peaks (1990) and the black lodge scenes with the man from another place.
BoJack brags to Pinky that his book will "kick your dick off." This might be innocent hyperbole, or it might be BoJack mean spiritedly reminding Pinky that penguins (like 97% of all bird species) do not have dicks.