Take a drink anytime the following are mentioned or happen:
The twins are (sun-streaked) blondes, a perfect size 6note In the "updated" versions of the books released in the 2000s, this was changed to size 4 and have blue-green eyes, perfect California tans, and dimples in their cheeks.
The identical lavalieres the twins both wear on a necklace, and the fact they got them for their 16th birthday.
The only ways to tell the twins apart are the facts that Elizabeth wears a watch (another drink if it's mentioned that Jessica believes "the party doesn't start until she arrives anyway") and has a birthmark on her shoulder, that Elizabeth usually wears her hair up while Jessica wears hers down, and that Elizabeth dresses conservatively while Jessica dresses wildly.
Elizabeth is four minutes older than Jessica (another drink when it's also mentioned "that it sometimes feels like four years to Elizabeth").
Jessica's room is a permanent gigantic mess. Another drink when she yet again borrows (usually without asking first) Elizabeth's clothes because she can't find her own, or doesn't keep up with her laundry.
Elizabeth poses as Jessica (mostly to get Jessica out of trouble) and/or vice-versa. Another drink if it's the twins' own parents whom she manages to fool.
Jessica tries to ruin the life of another girl if she perceives them as a rival or threat to her reputation. Another drink if the rivalry is over a boy.
One of the twins falls instantly in love with a cute guy they just met, or a guy falls instantly in love with one of them.
Todd or Elizabeth cheat on each other.
Anyone is hospitalized. Another drink if their hospitalization somehow relates to an attempted murder.
There is a school dance.
A holiday takes place more than once during the same year.
Elizabeth puts her nose in other people's business, or meddles in other people's lives. Add a sip if her friends or boyfriend complain about her neglecting them because of her meddling.
Against her better judgment, Elizabeth lets Jessica convince her to do something she knows she shouldn't do and/or that is morally dubious.
One or both of the twins are stalked. Change to a sip if one or both of the twins are mistaken for another woman being stalked.
A character is judged for drinking, using drugs, having sex, or being fat.
One or both of the twins receive an extremely prestigious job or internship. Another drink if this takes them outside the country.
Someone dies. Another drink if that someone had been dating one of the twins.
A girl reminds Steven of Tricia Martin.
Take a sip anytime the following happen:
Jessica has a temper tantrum.
Jessica uses the number 37, 137, or other random number ending with the digits "37" as her way to say "tons of" (it's her Character Catchphrase).
Elizabeth is mentioned to love writing, to write for the school paper or freelance for the town newspaper, or to want to become a journalist. Make it a drink if we see a sample of her writing. Make it a long drink if it's a poem.
A male character's favorite sport is mentioned: basketball for Todd, tennis for Bruce Patman, football for Ken Matthews, surfing for Bill Chase. Make it a drink if they are currently engaged in this sport and competing against an individual or team from Palisades High School or Big Mesa High School.
A scene with Jessica takes place at cheerleading practice.
Ned, the twins' father, when making some point to his teenage daughters, is mentioned to make his case to them just like he does when he's defending a case as a lawyer—because he's a lawyer.
Alice, the twins' mother, looks exactly like them and is often taken for the twins' older sister.
A scene takes place at one of the following local eateries: the Dairi Burger, Casey's Place, Guido's Pizza Palace, or the Box Tree Café.
A scene takes place at the beach or a swimming pool. Make it a drink if someone gets pushed or knocked into the water.
A scene takes place at the mall. Make it a drink if Jessica and Lila are shopping together.
A teen character has a party at their parents' house without supervision. Make it a drink if underage drinking is going on too.
Lila or Bruce brags about something. Make it a drink if Lila explicitly mentions her father, or if Bruce is bragging about something related to his skill on the tennis court.
Jessica mentions her love of pineapple pizza.
Winston Egbert wears a wacky outfit.
Anything is described as "Spanish-tiled."
Todd's eyes are described as "coffee-colored."
Steven Wakefield unexpectedly comes home from college.
Anyone has a cooking-related mishap. Make it a drink if it's Todd.
Elizabeth goes out to see a classic movie.
Jessica describes a guy as the most attractive male she's ever seen.
Mr. Collins is compared to Robert Redford.
Elizabeth is attracted to a guy other than her steady boyfriend. Make it a drink if she or another character discounts the possibility that she would ever cheat on her steady boyfriend. Take a second drink if she actually does. Finish the drink if the guy and her steady boyfriend get into a physical fight over her.