Simply, its where one places an apple
pie (Favorably, the Kipling variety is used) over the receiving chaps
anus, and begins anal intercourse with the said arsehole essentially crumbling up the apple
pie over the rectal passage. The end resulting jizzy pooey apple crumble is then shared, A delacasy in certain parts of the world.
The act is not strictly kept to the gay community however, no known documentation of women trying
Bert's Apple Crumble have been found.