Dom speaks:
Verbal brain farts are a regular part of Largo's day, especially when it comes to Erika's more salient features. People should be used to Largo coming in from right field to talk about girl parts.
I'm sure other people can find the links to things like Racked and other such parts where a Largo conversation trails off, pauses, and suddenly turns to boobs. (Heck, I'm sure people have anecdotes about friends who've done the same thing).