Sometimes females will do that if they are about ready to lay their eggs. Have you witnessed an actual mating between the two and if so how long ago? It could be that she is gravid. :)
:I've heard that Russian males (tortoises, that is) are aggressive during courtship, but can the female exhibit this behavior as well? I'm about 99% percent sure of the sexes of my torts, but today I witnessed head bobbing and and an aggressive move where my female flipped the male on to his back. She also does a lot of mouth opening (no sounds though). The male seems a little interested, but she's pretty rough. Any insight?