Sleep after sex? It's natural

A new tome Why Do Men Fall Asleep After Sex? hit stores Tuesday.

Sorry, ladies. It's not a self-help book for your man.

The follow-up to the best selling Why Do Men Have Nipples? is parthumor, part health info, answering questions, as the authors say,"you'd only ask a doctor after your third whiskey sour."

Penned by New York emergency room physician Dr. Billy Goldberg andhumorist Mark Leyner, the new effort, published by Three RiversPress, covers the same kind of queries as Nipples: "odd, icky, kinky,noxious, libidinous or just plain embarrassing" health-relatedwonders.

Goldberg, 40, a doctor for 15 years, said the books came out ofquestions …