Is this happening to you?
Just like the clown post I wrote the other day, it seems like there’s one of these in every crowd too. There are some folks out there who consider themselves a manager though they do not possess the proper title in order to actually manage anyone. Some lines you just don’t cross.
It is one thing when a coworker asks for your help with something, but another if he or she demands it as an order, thus assuming your manager’s role. You should only report to one person, and that’s your immediate manager/supervisor. He or she should know what your work load is and whether or not you can be “lent” out to help someone else.
Some advocates advise assuming a role as a manager in order to actually obtain the position. This hardly means that you start supervising others on your own. You should only assume certain tasks that your current manager approves.