Sally, of course, means steam from radioactively superheated rock, as volcanoes Just Won't Work on a planet that is technically a giant sponge filled with water.

Transcript

{scene cut to Padmé cleaning R2}
Padmé: <sigh>
Jar Jar: Hi, whatsa happening now?
R2-D2: Oh, it's you.
Jar Jar: Mesa can tell yousa one smart droid!
R2-D2: So, uh... Sally. What's this artefact you're looking for?
Jar Jar: It'sa da Lost Orb of Phanastacoria. It'sa mighty bombad weapon!
R2-D2: Hmm. Tell me more...
Jar Jar: It'sa from Otoh Gunga. But it got stolened!
R2-D2: Otoh Gunga?
Jar Jar: It'sa hidden underwater city, mades of glass bubbles, powered with clockwork and steam from volcanoes!
R2-D2: Wow, that actually sounds cool. I guess the GM has some creativity after all.
GM: Hmph. You need to speak in beeps.