Kris, my clowns lay a new clutch of eggs every 11 days, like clockwork.
What they did the very first time (over two years ago) was to prep the smooth surface that they prefer to lay eggs on. They chose my wall hammer (and have since killed a 15" beautiful hammer :sad2: ) to lay their eggs. The male will shake violently as stated above. However, I saw my pair alternate rubbing their bodies on the smooth surface of the hammer. They did this for a few weeks.
At first I thought they had parasites because of the constant rubbing on the hammer. Then I saw them become a bit more territorial. Then I finally saw the eggs. Ever since then they have laid the eggs on day one. Nine days later, two hours after lights out the eggs would hatch. Hundreds of babies could be seen swimming around for a couple of hours, before they all became a smorgasboard for the rest of the fish. Two days after the eggs hatch, the next clutch of eggs was laid (day 11). The cycle continues to this day. Although, they finally killed the last bit of hammer. Very bummed about that.
Here's a pic of the hammer in its heyday. You can even see one of the clowns in it. :sad2:
swimmer