Georgiansilver:

Entering the haggis was indeed outlawed during the last century but it is still rumoured to be practised in remote areas of the highlands.
The custom was first mentioned in professor Duncan Biscuits' "Perversions In the Scottish Highlands" or P.I.S.H. as it became widely known. In it he describes the ceremony surrounding the entering of the haggis from when it is piped into the hall before the assembled gathering to the tune of "Duelling Bagpipes", to the lifting of the kilts and finally to the aforementioned entering.
As a test of manhood it is only allowed when the clan elders are satisfied that sufficient expertise has been gained at the "Tossing of the Caber". The "Tossers" can then be elevated to the position of "(S)haggis of the Clan".