AYou lay out a piece of plastic wrap, put some frosting on it, then roll it up like a sausage. Snip off one end, then drop it into a piping bag. It is less messy and you can easily change colors.
AIt is also called a frostin/icing plug. Here is a video that shows how to do it.
http://www.youtube.com/watch?v=QxE-pnqmsE0&feature=youtube_gdata_player
I love this method. It eliminates 80 % of your clean-up. When you are finished, just pop that plug out and into the trash and your bag only has icing down by the tip. And if you want bi-color icing, just lay down a strip of each color and roll it up. I have seen where people but in a plug of each color, but haven't tried it.
AOh, I didn't make the video, just found it by a google search. Sorry if I was confusing.
I do it as well. I just lay out the wrap on my counter but it depends how thin you make your icing as well. If you have really thin icing I'd use the method Folkette suggested, in a container first. I either tie the ends or use a small twist tie.
Quote by @%username% on %date%
%body%