I did. Not so easy. Easiest might be to get a 30 day multiple entry. Depends on what area of Russia you are planning, but I would highly recommend to cross over to Mongolia for a few days. Danger with that is you might not wish to go back to Russia.
I will wave back to anyone, bikes , mopeds ,Vespas, kids ......
What I can't get is all these on bike hysterically waving guys / girls , that when they stop at a gas station , ferry etc will not even nod or say hi.