Yes, molding just the same as a clay sculpturing. Molding in the simplest terms is tweaking till whatever your doing, is to your own perfection. The limit to molding is palace restrictions, and your imagination.
Believe it or not you do not have to know how draw to make new avs or clothing for avs. Simply all you need to know, is how to erase, and everyone knows how to erase! So heres how you can start making your own avatars instantly! Most if not the majority of my avs/art is are made using all or some molding to get a desired shape. The simple way to do it is to, fill with pure black in/on a new prop and erase to make/mold that square into a circle, or into any form you want until your happy, then with the shape done to your perfection fill in the black silhouette NOTE: Leave an outline! Like in the image below). with color, then add shading. Then you should be done. Look at the image below to get the best idea of what I mean.
That's about it for molding. Not much to it really. If it's hard then your doing a good job, if its easy then you shouldn't be reading this cause you know how to do it. (BTW- Im sorry for the image being so damn big)