Lisa Langlois said that she didn't think the script was funny, but during her audition, everyone was cracking up laughing. She realized later that they had all been snorting cocaine.
According to Lisa Langlois, this was the only time she ever cried on a film set. When a producer asked why she was crying, she replied, "The fact that you don't know why I'm crying is why I'm crying." She explained in an interview that it was because the managing of the entire production was a muddled disaster, and she had been forced to run around outside for hours in the cold, including running through filthy creeks, after being pressured into performing fully nude by producers.
Lisa Langlois reportedly beat out both Jennifer Jason Leigh and Christie Brinkley for the starring female role in this film. If true, the other two must have auditioned based on the original PG-rated script, which didn't involve full nudity. Leigh, who was nude in Fast Times at Ridgemont High (1982), may not have had an issue with the added nudity if she was cast, but it's doubtful Brinkley would have agreed to take her clothes off.
The "invisible" liquid featured in the little glass vials was blueberry Kool Aid.