Concerning Jawa juice, this definately belongs in the lets-f**k-with-suspension-of-disbelief category. Just like the Tarzan yell, Jar Jars dive, the two headed Podrace announcer etc. etc. Obviously todays special at the Coruscant diner (also an offender in this category) has to be "Jawa juice"
I think Lucas is simply confusing his future merchandise with good ideas for beverage names in Star Wars.
How to juice a Jawa? You squeeze it until it yells untiniii!!