Penile Flutter

An involuntary muscle spasm located in the male genitalia. This spasm can last for two to seven seconds, and causes can include sexual stimulation, sexual over-stimulation, urination, electric shock, or extraneous sensory perception. No medical attention is required, although you should contact your doctor if you experience a penile flutter lasting longer than four hours, or if redness or discomfort occur.

"Oh man, that girl at the end of the bar totally gave me a penile flutter."

Penile Flutter by Dr. Tobor March 4, 2011