You can tell how a man is in bed by how he dances.
This is an old wives' tale that shows why no one listens to old wives. So if a guy does a mean limbo, it means he doesn't struggle with premature ejaculation? And a gentleman who can tango is less likely to have a defective unit (if anything, a man who voluntarily tangos probably has some damage down below that could lead to a lucrative malpractice suit. Gives new meaning to the phrase sitting on a goldmine...).
And why doesn't it work the other way? Seems to me you can probably tell more about a woman's sexual abilities--flexibility, ability to absorb impact (if the woman you're dancing with takes punishment like a tackling dummy, you're in for a good night)--by watching her dance than you can from watching a man boogie.
Men don't tell old wives' tales because men are 1,000 times better at profiling. If a woman is a cold fish at the bar, a man knows she's going to be a cold fish when you get her home. If her whole body quakes each you brush her finger, you know her body is a one big, raw erogenous zone. If she has an Adam's Apple that extends past her overbite, she's probably isn't a she.
Men don't turn the obvious into a "CSI" episode, and when a woman's sexual disposition isn't obvious, men don't resort to bizarre numerology involving how far apart her nipples are. When a man is on the prowl, his mind is occupied with trying to figure out which of the sixteen fake versions of himself he's going to need to display to take that woman home. He doesn't have time to glean esoteric info. from her eyebrows.
The You can tell how a man is in bed by how he dances old wives' tale should suffer the same fate as actual old wives; permanent exile to the fringes of society.