The part of the female body, which inexplicably measures temperature to be alot colder than it actually is. There is no male equivilant.
Girl: Im cold, can i have your jacket?
Boy: No, thats just your femmometer, your fine really.
Girl: No im actually really cold.
Boy: HOW THE FUCK CAN YOU BE COLD, ITS THE MIDDLE OF FUCKING SUMMER, IF YOU KNEW WERE GONNA BE COLD, THEN WHY DIDN'T YOU BRING YOUR OWN FUCKING JACKET, YOU FUCKING RETARD. AND YEAH I DID SLEEP WITH YOUR SISTER AS WELL, AND WHAT.