How would I go about irritating it? I've never really seen the tissue retract all that much, even when I had to truck it home via bus.

A little tough to tell from the photo. Might be easier to id once it grows out a bit more. I have a coral in my system that was sold to me as a 'chalice' some years ago at a Kamloops swap. It looks more like a green plating monti now that it's grown out. By the looks of your photo it might actually be something similar if not the same as what I bagged. Here's a link that may help. I suspect mine is an Echinophyllia aspera, perhaps that's what you have as well.

http://www.tfhmagazine.com/details/m...lia-aspera.htm

I had some additional links in another thread, but none of them work any longer. There were several other species similar. When I get a bit of spare time I'll try to dig up the thread with valid links.

So the other thread I was referring to is a coral swap meet in Kelowna in the BC Interiors forum. Rather than try to research the dead links, it seems I came to the conclusion my frag (similar looking to your photo) may be a Montipora foliosa & I wished to pass that info on to those who bagged a frag. If you search the web for M. foliosa, you might find a match. They seem to come in many different colours, including green.

I've seen Montipora foliosa listed with an English name of Chalice Coral & Echinophyllia aspera called a Symphony Coral on the same web site so that simply adds to the confusion. Give it some time to grow & ID might come easier. HTH.