The rubber gasket, eye piece hood, on the the rear spot meter section has come off its base. Do you have suggestions on how best to replace the rubber gasket (eye piece hood) back into its correct position?

There seems to be some "play"(looseness) with the specific eye piece and one is able to turn the eye piece left and right, perhaps tightening the eye piece on the gasket if it is in its proper position, and of course it is now not in its proper location. I did not want to "force" the removal of the rear unit. suggestions

Thank you