It could take up to a week for them to fully come out. I had one open in an hour and I had one closed for 3 days. I moved it to a different part of the tank and it opened later that day. It all depends.
They don't just "stick" to the rock. They have to grow onto it. You can glue it to the rock with super glue gel, but then it would be there for good. What I did with my smaller cutting was glued it to a small piece of rock. It will grow and cover the rock and then I can move it where I want it, if I change my mind.