This is a synonym for a penis in porn films. It is derived from the ability of an experienced penis and its experienced user to determine the suitability of a vagina, breast, anus or in fact any other body part for fucking or coital relations.
Typically the barometer functions by being slapped or thrust vigorously through or against the body part under test.
Instrument used to measure the shit pressure in the atmosphere. Used to anticipate a shit storm and potential influx of shit hawks; whom may either spread their shit or swoop down and take humans away to the shit nest.
"Do you know what a shit barometer is bubs?" "It measures the shit pressure in the atmosphere" "Your ears will implode from the shit pressure"
When you have extreme BSTL(balls stuck to leg), and u physically remove the package from its upwright position. To perform this maneuver, you must make ur legs into a 45 degree angle. Then dip ur knees causing for seperation of the co-hedrant package.
Woman: what the heck was that?
Man: i had some sweaty package, so i pulled The Barone Tuck.