I have 5 wonderful leos *g*, most of whom are in separate tanks. I've noticed though, sometimes two of my females will lift their tails high in the air and swish them slowly from side to side. One female that does this shares a 30 gallon tank with a male, but the other has always been in her own tank. I'm curious as to what, if anything, it means. 
Also, I read an earlier post about how someone's Leo would lay on its belly and stretch it's back legs out, mine do the same thing when they're "sunning" themselves under the heat lamp
