The world's a mean place. It's unfair, then it's fair. It's hateful, then it's loving. It's a very peculiar place on philosophical and metaphysical and religious levels.
There is a lot of rubbish written about toilet humour - people saying it is childish and pretending it is beneath them - but there is no doubting the effectiveness of a really good willy gag.
The Blind Boys are truly the deepest well of American musical heritage you can discover.

