It is the elevated form of duper. Kinda like charmander to charzard. Its that kind of leap which establishes Jupiterdupiter above just duper itself. At duper you may feel as high as the moon, if that, but when at Jupiterdupiter levels, ur actually one of Jupiter's 63 known moons.
Stoner 1: "Yo, wanna blaze."
Stoner 2: "Nah, I've got class, I'm not trying to get Jupiterdupiter."
Stoner 1: "Come on man."
...10 minutes later
Stoner 2: "Yo, I'm sooo Jupiterdupiter."
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.