you're not actually supposed to
it's an illustration of anti-humour.
(
bananaman,
Thu 1 May 2003, 19:54,
archived)
two nuns in the bath, one says 'where's the soap'
the other says 'look for it youself I'm having a wank'
(
Mattyboy,
Thu 1 May 2003, 20:10,
archived)