half animal has a mirror. Can I move the tail from one side to the other? I have modeled with a mirror. Now I want to do the tail. The tail has to move from one side to the other but I can't because half animal has a mirror. 

When I try to move the tail from one side to the other, this is the result.

Is it possible?  Can I take off the mirror just in the tail?
Another alternative is to keep the mesh symmetric with the tail in the center, and then add an Armature with bones to control the tail and then pose the armature to make the tail off-center.

The order of the modifiers (mirror and armature) are probably important.

Edit:  is a .blend file illustrating the technique and proving that it is possible to pose a mirrored mesh without applying the mirror modifier (leaving it as a modifier).