The *-eroo* suffix works as an intensifier of sorts, though it seems to have other less well-defined properties as well.

The online OED has only this to say about the *-eroo* suffix:

> **-eroo**, suffix  
      factitious slang suffix as in *boozeroo* n., *brusheroo* (brush n.2 8b), *flopperoo* n. U.S. formations  
  in *-eroo*, *-aroo* (e.g. buckaroo n.) are discussed in Amer. Speech (1942) XVII. 10f,  
  and in T. Pyles Words & Ways Amer. Eng. (1952) 199.  

> 1964   ***Guardian*** 8 July 7/6   Those jerkeroos feel embarrassed.

Etymonline's gloss is similarly disappointing:

> The meaning [of *switch*] "a change from one to another, a reversal, an exchange, a substitution" is first recorded 1920; **extended form *switcheroo* is by 1933**. (Emphasis my own.)

I would like to know where this suffix comes from and, if possible, why there isn't a better etymology. Any ideas?