[Dan Zollman]

I just tried it, and it won't let you mate something to a geometric point unless it's a work point. Try creating a work point (choose the axis of the pencil and the conic surface of the pencil to create a work point at their intersection), then mate that point to the surface. That way you'll still be able to move the pencil around on the surface.

To constrain it standing up, create an angle constraint between the pencil axis and another edge or axis.