Okay, so this is half technique, half disclaimer. I was beating off tonight on Webcam and my friend suggested that I try to cum in my own mouth. Being the adventurous soul I am, I decided to try it. I sat upside-down with my back and butt against the back of my chair and my legs against the wall (my head was resting on the chair) and had one of the most pleasureful orgasms of my life as rope after rope of semen sprayed my face and mouth. (A side note: It's not a bad thing to taste your own spunk every now and then--keeps me familiar with my own product.)
Here's the warning, though. A spurt of semen splashed up in my eye and, though it didn't hurt too much, it caused severe redness for almost two hours. Be very careful if you try this one, but be sure to do it at least once.