I don't know-- looks like they are trying to figure it out, but it doesn't look like a lock to me.

I think that maybe if you leave them alone they *will* figure it out. When I put my male in with a female, there is female tail wagging and they usually have a lock with their tails in the air for a while. Then they put their tails down and it is clearly belly-side tail to belly-side tail with definite tail tip curl. Does this make sense? Also, mine tend to stay locked for half a day to an entire day before they separate; even if I interrupt their privacy for a second.

I'm just trying to help since it is very disappointing to believe that eggs are on the way, and yet the incubator that is all set up and running is empty