I use the bottom base on a clay pot in their area. Is say they lay on the pot once every three times. Works good just don't remove too early or expose to air!
Mine "host" the small terra cotta
all the time. Whether it has eggs in it or not.
They have never spawn anywhere but there.
They both stay in it all night. From the minute the lights go off, they are in it and they stay until the lights come back on. It's their home. They work hard to keep every gain of sand out of it.
And when I switch the pot out for cleaning....I have learned that I need to put the clean pot in BEFORE I take the dirty one out or they will THROW A FIT!!!
They start making the sand bed fill the water column.
I always know when the tank gets a little cloudy, the clowns are tee-d off about intruders (Usually a snail) too close to their little pot. They are totally OCD with that pot!! It's a necessary part of my reef tank even if it looks odd