Tiddlypush (Word of the Week)

I have a tendancy to overthink things and I've been wracking my brains trying to think of a deep and significant word to be our first ever word of the week. I've given up however, and decided instead to go for a nice inane word that makes me grin somewhat. So, here goes our first ever Word of the Week is:

Tiddlypush
A colloquial noun that turned up sometime in the mid 20th Century, so not that old in the word stakes. It has two meanings that I've come across
1) A nonsense word meaning 'goodbye'
2) A person or thing whose name is unknown, or is indelicate to mention.

The Shorter Oxford Dictionary suggests that it is similar in meaning to: thingy, thingumajig and thingumabob. I guess we could add whatjamacallit, whatsisname and doohickey to the list as well.

I particularly love the idea of it being used for someone that it is indelicate to mention, perhaps the mother-in-law?

Sources:
Shorter Oxford Dictionary (2 volumes) 6th edition, 2007.
A Dictionary of Slang and Unconventional English, 2005 by E. Partridge and P. Beale

Von