Okay, some of you would have got that reference, while others are now mystified as to why that line immediately above is there.
We write these comics in a meeting room during lunchtime at work. Someone brings a laptop and we hook it up to a projector and we look at our file of script ideas and take turns yelling out ideas and denouncing each others' ideas as terrible. Somehow at the end of this process we end up with the scripts we use.
Once we'd more or less completed this one, one of us stood up, walked over to the computer, motioned that he wanted the keyboard, and typed in the following line:
R2-D2: Third base!The entire room immediately cracked up in fits of hilarity. Except for one of us, who didn't know what we were laughing at.
The line is a reference to Abbott and Costello's most well-known comedy routine, Who's on First? (For those of you not familiar with it and who would like to see it, there's a video here.) Despite being a distinctly American comedy routine, based around a discussion of baseball, it has entered the common consciousness of western culture - so much so that all but one of us Australians were familiar with it.
Those of us who got the reference thought it would make an excellent punchline, as it seemed to fit the talking-at-odds nature of the dialogue in this strip so well. The other guy argued against it, since (and he did have a point) there would be people who simply didn't get it. We argued back that the people who did get it would find it gobsmackingly hilarious, as evidenced by the fact that we were still giggling uncontrollably over it several minutes later.
So it stayed in the script. A few days later, one of us assembled the screencaps and put the strip together. With the "Third base" line in it.
And we all looked at it again in the harsh light of day and collectively went, "Naaaah.... that's not going to work."
There are a couple of reasons. Firstly, it really is a bit jarring, pulling the reader well out of the thin veneer of Star Wars-ness that usually overlays the dialogue. Secondly, "third base" has a sexual connotation in American slang and, given where R2 is standing in relation to Padmé in the final frame, and the previous strip where R2 requested a beautiful handmaiden to clean and oil him... well, it was straying into territory where we really, really don't want to go.
However, even given these reasons for not including the line - which we have ultimately decided are strong enough not to include it - we still think the line itself is inherently funny. So we didn't want to leave it out entirely, and bumped it down here to the annotation, where we can safely dissect it in a semi-intellectual manner without endangering the style and the PG-rated nature of the comic itself.
GM: You enter the dingy spare parts shop. It's owned by an alien.
Jar Jar: What's hesa look like? Does hesa has wings?
Qui-Gon: Hey, flying dude! We need guns!
Watto: Eh. Um. What sort of guns?
Jar Jar: What'sa yousa name?
Qui-Gon: Really big ones.
Watto: What? Oh...
Jar Jar: Hello Watto!
Jar Jar: Wow, yousa can fly.
Jar Jar: Mesa bets you never falls off stuff.
Watto: I need more details.
R2-D2: We need replacement shield generator parts for a—
Jar Jar: Oh, yousa blue, and has big webbed feet...
R2-D2: <sigh> Biddle booop.
Qui-Gon: My robot here has a readout of what I need.
Watto: Oh, a J-Type 327, eh?
Jar Jar: ...andsa biiig wrinkly nose, and tusks...
Watto: Where do you want these installed?
Qui-Gon/Jar Jar: Right under the nose!