From what I've read it seems that it's a bad idea to cover central air conditioning vents. So what can I do to control the cold air coming through one vent without lowering the AC for the rest of the house? It needs to be easy to put on and take off as needed.
Is there any type of insulation or absorbing material that would absorb the cold part of the air and not block the airflow?
(Additional non essential info: We have one small room in the house that has a central AC vent, and because it's a small room it gets cold very fast. No window in the room.)