Fair Isle Knitting- steeking?

I am doing the fair Isle knitting right now but don’t understand what they mean about (Steeking)? The pattern says to sew down all the little ends of colors and then cut it open. Woudn’t that cut all the colors loose?

Help please!!!

I think Silver can really help you here. I believe she made a fair isle sweater with steeking…

http://www.knittinghelp.com/knitting/forum/viewtopic.php?t=4045