How on earth do you hook up a boost gauge?

Some of you may know what im talking about, theres a lil ring type thing that slides onto the hose and then that holds the hose in place while something else slides on top of that to connect it to the boost gauge. Ive dont it before but i cant get that lil ring onto the hose. I tried sandpaper, cutting the hose in half/four, cutting it at a angle, is there a special way to do this?
 
i think it is called a ferrule. they can be a real pain. JR is right. depending upon the type of line used, i have shaved the line down to kind of like a point. i silicone spray the line and slide the ferrule on. once it is started once you get it to the point of where it is sliding over the full O.D., it slides alright. then cut the spear head flush so it seats.

good luck.