I've heard two, both, to give the 'sanitised' version are names for
small bits of excrement which are difficult to dispose of. I seem to
recall (I think) Jimmy Connelly building one of his 'monologues' around
one of the descriptions, it involved flushing a loo numerous times.
Of course, such terms go back years and may well have multiple claimed
derivations. I don't recall it hearing it outside of the Tyneside area,
unless the speaker was a northerner, but I expect other areas have
similar versions. A number of Geordie terms are common to those used in
parts of Scotland and, to my surprise, Norway- something I discovered
when at Uni, one of my fellow students was from Norway and, at the time,
I did use Geordie terms from time to time. Over the years, my accent has
mellowed. 'Yem' (home) was the one he spotted and led to the discovery
of some others.
I can't saw I've read Viz much, not really my kind of humour. Is it
still published? There was a fan of Viz on the group who produced
'uk.ra' versions from time to time.