In the first draft of the script, the infamous "Pudding!" line and pants dropping act was done by Sam. However, when they went to shoot Jared Padalecki and Jensen Ackles, Sam and Dean respectively, changed it to Dean on the spot without telling anyone because they felt it fit his character better.
When Sam asks Dean how he is doing, Dean replies "I just got thraped". "Thraped" is a slang term for when someone has therapy forced upon then against their will.
This is the second time Sam & Dean have used the last name Babar, which is a direct reference to the Chevy Chase movie Fletch (1985). They even use a quote from Fletch, when the Dr. asks if there is a children's book about an elephant named Babar & they reply that they don't have any elephant books.
In other reference to Kesey's One Flew Over the Cuckoo's Nest (1975), there's a patient dancing in the exact same manner as one of the patients in Cuckoo's Nest.
The aliases Sam and Dean use are Eddie and Alex. Eddie and Alex are the two brothers in the band Van Halen (Edward Van Halen and Alex Van Halen, for whom the band is named). Yet another Supernatural tribute to classic rock bands.