the male penis... but unlike many antennas, this mantenna can only be used properly by a female... unless your gay.
"Oooo... look at the mantenna go up!"
by D&J November 15, 2002
A man's penis, specifically in the erect position.
My mantenna is detecting some estrogen in the area, so I should follow it to find the girl of my dreams.
by Marcus Solomon October 30, 2007