Posted by R. Berg on February 10, 2005
In Reply to: Aah Diddums posted by adam slater on February 10, 2005
: as a notoriously sulky, heavily complaining individual, I was wondering as to the origin of the expression 'aah Diddums' said to add faux pity.
Apparently it's baby talk, used sarcastically. Eric Partridge, A Dictionary of Slang and Unconventional English has an entry for the exclamation "Diddums!" alone, without reference to the use of it that you describe. "Did you (or did he, etc.) then!: nursery colloquialism, in consoling a child: late C. 19-20. . . . By perversion of 'did you' (or 'he')."