Most "instructional" sex tapes are pedestrian; this latest volume of "Dr. Joel Bross's Encyclopedia of Sexual Expression" is like the Russian Army trudging through your VCR. The droning, banal, barely-audible advice from the back-to-the-camera Dr. Bross includes painfully obvious tips, like asking your partner to do things to you that he/she isn't doing that you would like him/her to do. The ho-hum sex scenes are as lively as wilted spinach. It's like reading a cookbook by someone who doesn't like to eat.