The feeling of euphoria and/or sexual stimulation upon hearing an especially good riff or breakdown written by Chuck Schuldiner, frontman of the american death metal band "Death".
A Schuldner-gasm may be followed by any of the following: Ejaculation, tears of joy, muscle relaxation, etc,.
I was listening to "Empty Words" by Death, and when the intro ended and went into the main riff, I had a Schuldiner-gasm and creamed my jeans.