How not to write sex scenes

At The New York Times, Sarah Lyall writes about an eternal problem of literature: " A writer's tumescent member is a reader's risible euphemism"

In a climactic sex scene in the novel "Golden Hill," set in mid-18th-century Manhattan, Francis Spufford's narrator briefly steps outside the story to grumble to the reader. "How hard it is to describe a desirable woman without running into geography! Or the barnyard. Or the resources of the fruit-bowl," he complains. "I do not want to write this part of the story."