の zaniness

Okay, I know that the particle "no" makes a noun following it into an adjective for the noun in front of it, or makes it a possessive (女友達のあんた, "your girlfriend"). But what does it mean when a conjunction (ie. "と" = "and") is put in there? For example: 女友達とのあんた or 委員長そしての仕事.

（　委員長そしての仕事を…でもこんな格好で学校にいるなんて…気が付かれたら私…　）

from F-ism #9 (bondage); caption to this pic:
http://orz.4chan.org/d/res/145401.html
AFAIK, the second part means something along the lines of "doing this in school...if someone notices me..."