In the early 1970s, Dr. David Reuben wrote a very serious sex- instruction manual which became a best-seller. Confronted with this epic of instructional erotica, Woody Allen decided to adapt this book to the screen, which was divided into a number of individual ''topic episodes,'' such as ''Do Aphrodisiacs Work?'' (this episode has a classy Shakespearean tone), ''What is Sodomy?'', ''Why Some Women Have Trouble Reaching Orgasm,'' ''Are Transvestites Homosexuals?'' and a grand finale: ''What Happens During Ejaculation?'' in which Tony Randall is an inside- the-body sperm-bank operator who sends Woody out as Sperm No. 2--an excellent position--except that almost-triumphant sperm Woody finds himself up against a 400-foot diaphragm!... Also starring John Carradine, Burt Reynolds, Lynn Redgrave and Regis Philbin.