Using an erg properly.

I believe the proper use is uttering it after you've hit yourself in the groin with your bike's handlebars.

Good for you for asking, I always see people using the erg incorrectly at the gym and it drive me insane. It's hard to put all of the stroke's little parts into a brief synopsis, so here are some main things to remember:

The rowing stroke is really 70-80% the leg drive and the rest or the power comes from the hang/follow-through of the back and finally the arms. When you take a stroke you want to start at the "top of the slide" close to the fly wheel with your legs bent, arms straight and back straight yet angled slightly forward like you are leaning over. Push off first with your legs to begin the stroke, you want to have your legs almost totally flat before you open your back and pull your arms in to complete the stroke. The key is to have a smooth transition of power from the legs to the back to the arms, and feel a bit like you are hanging on the bar with your arms straight before you pull in your arms to finish off the stroke. To "recover" which means getting back in position to take another stroke you want to lead with your arms straightening again, followed by your back leaning a bit towards the fly wheel and finally bending your knees and slowly moving up the slide on the seat to the "catch" where you are coiled up at the top of the slide.

If you are learning to use the erg try to isolate the different movements to get the hang for how they work together and focus on a slow recovery (the time it takes to go from finishing the stroke to being coiled up back at the catch again. I wouldn't try to go any faster than 24 strokes per minute when you are learning the stroke.

I'm sure some other ex-rowers will chime in with good tips and/or correct some of my description.

Thank you!

 
 That's funny right there.

Calimavs and Richman have some good advice there for getting started. The only thing I would add is, at the Finish (Catch - legs - back - arms - finish - arms - back - legs repeat...) make sure you are keeping you hips/butt straight still. You want to make sure you do not roll back on your hips as this could cause issues for the muscles in your lower back. Basically, for the back portion of the stroke just keep your but still and pivot your entire upper torso from the hips.