The rod is as thick as a person's wrist, is bright red, and is smooth and round. It seems to be made from stone, though it is soft to the touch.
The exact use of the rod is unknown. The ter'angreal made Elayne think of fire when she held it, and when she channeled fire into the rod, she lost consciousness. Upon awakening, everyone refused to tell her what happened and struggled to keep from rolling on the floor laughing.
The evidence, including the shape and flexibility of the rod, seems to indicate that this ter'angreal is some sort of sexual aid.