Railroading

The degree of determinism in a tabletop game. Railroading occurs when the GM has a particular story or sequence of events planned out and will not allow the players to deviate from it.

A small amount of railroading occurs in nearly all campaigns and is considered reasonable and necessary for a satisfying story. Excessive railroading, however, destroys the illusion of freedom that RPGs provide and alienates the players. For this reason it is important that a GM be able to improvise when his players go off the trail he's marked out for them without simply forcing them back onto it again.

If you feel you're being excessively railroaded, it is common to make a "Choo choo!" noise, or other train related sounds. Alternatively you can say "That's railroading and that's wrong," every time he finishes a thought.