Constrainting axes through multple steps.

Hi. I have a modeling question. I was trying to extrude a polygon by one edge to make a ramp. I just wanted it to move it over and down and not to the side at all so I extruded and then hit ctrl+shift x. To have a nice curve to the ramp I needed to extrude and move the edge often but every time I have to hit ctrl+shift x to constrain the axes again. Is it possible to toggle the constraint on for a period of time so that all i would have to do would be to hit x to extrude then move the edge? I am using 2.46. Thanks for reading and thanks for any replies in advance.