Continuity mistake: When Pee Wee walks up to the bums at the drive in, the soda falls over in the holder in his right arm. When he steps in to give them their snow cones, it's instantly standing again only to see it fallen over again when he watches the fight scene with the ninjas on screen.
Revealing mistake: Throughout the studio scene where Pee Wee is shot from the front being chased by security, the fact that his bike is on a rig can be seen by how rigid the bike is when he pedals it and it doesn't move side to side like it does when he's riding it freely in all the other shots.
Revealing mistake: After the bar scene where Pee Wee leaves riding the motorcycle, we can see it's a stuntman, given the different physique of having wider shoulders and a fuller head of hair than that of Pee Wee.
Continuity mistake: After throwing the candy to the bikers, Pee Wee is holding a box of Milk Duds and a candy bar. After he watches himself in the movie, the candy bar disappears then reappears behind the Milk Duds between shots. Then in the next shot of him skipping towards Dottie - all of the candy disappears completely.
Other mistake: The security footage that Terry shows of Pee Wee going through the Godzilla set is simply a black and white version of the same footage we see as movie watchers of the film, not from the camera being used to shoot the movie.
Continuity mistake: When Pee Wee is dressed as a nun on the sound stage, he looks impatiently at the bike - we see only a shadow from the bike on the left side. Then from the front shot, there is now the shadows of the actors right all behind the bike which weren't there in the prior shot.
Answer: It was some sort of gag gum (popular in the past) that either had hot pepper/cinnamon or simply tasted terrible.
Brian Katcher