The term "twinkie defense" is a derisive label for an improbable legal defense. Its origins lie with the trial of Dan White for the assassination of San Francisco City supervisor Harvey Milk and mayor George Moscone. The defense argued that White's consumption of various junk food worsened his depression thus his mental capacity had been diminished so he was incapable of premeditation. He was instead convicted of voluntary manslaughter. The satirist Paul Krassner would claim credit for coming up with the term.
If indeed Carrie and Justin were in bed together, naked, but just kissing and touching then it is true that Justin cannot be charged with rape in the third degree. But her mother did see that their nude bodies were pressed up against each other and Justin was touching Carrie's breasts under the blankets, which means Justin could be charged with sexual abuse in the third degree, which is when one person subjects another person to sexual contact (direct touching of the breasts, buttocks, penis, scrotum or vulva) without the other person's consent OR when a minor over the age of 14 is subjected to sexual contact by another person over the age of 21. Sexual abuse in the third degree is a class B misdemeanor and carries a penalty of a $500 fine and up to six months in jail.
Danielle Panabaker later starred with Law & Order (1990)'s Jesse L. Martin in The Flash (2014), as Caitlin Snow and Joe West, respectively; when they meet the eponymous speedster in season 2's "Trajectory (2016)", and Joe introduces himself as a police detective, Trajectory retorts "How very 'Law & Order' of you."