Maybe what you are seeing is the start of courting? Mine will do "crunches" when they are courting. They bend at the pouch and the pouch opens...I guess preparing for eggs. They also turn colors when courting there lady friends, hold tails and dance around the girl. It's actually quite a display, and IMO unmistakable courting.
For all the courting I have seen, I haven't witnessed any egg transfers...but I know they are getting it done...the proof is in the pudding...fry every 15 days or so!
Carolyn