To steam milk the real way, start with a cold metal cup with a handle on it, a steam wand on an espresso machine, and some cold milk. The colder the steaming cup, the better. Before you start, wrap a
towel around the end of the wand, and send a few short bursts of steam into the rag, to clean it out and get any residing water out of the wand. Be very careful not to grasp the rag around the tip of the wand, or that steam and hot water will shoot straight through the rag into your hand.
Next, pour your milk into the steaming cup, and put the wand in the milk. Once the wand is submerged, turn on the steam and hold the cup in such a way that the tip of the wand is about one to three below the surface of the milk, and hold it still. People who bob the milk up and down do not know what they're doing. Don't do that, it ruins the little foam you'll make. Now for the foam part. Since this is steaming milk, and not frothing milk, we're not gonna make a lot of foam.
Once the cup is warm to the touch, lower the milk cup so that the milk starts to rumble a little bit, but not to the point where it starts whilstling as that can ruin the foam too. Just hold the milk there for about fifteen or twenty seconds, and then raise the milk again to finish steaming it. Now, the whole time, you should have two hands on the cup, one on the handle, and one sort of cupping the bottom. When the cup gets so hot that you can only hold your fingers there for a second or two, you're done. If you have a thermometer, the optimal temp is 160 degrees.
There is also a distinctive change in pitch of the steamed milk when it reaches this point, that you will learn over time. Now you have some steamed milk, so make an espresso drink! (see latte, mocha, cappucino)