I suggested the easiest way, which is what you were looking for, but if you want to make it more believable you'll probably have to do a bit of research and tutorials. A lattice is a deformer, try experimenting with it (it's in the animation module under create deformers I think). A cluster is a handle that can move multiple vertices (refer to Maya help on more info on how to create them). A vibration expression isn't anything specifically in maya, I was simply saying that you could use an expression to drive the motion making it look more like a vibrating string. You'll probably have to do a few tutorials to learn about expressions. Maybe I shouldn't have suggested it. Go with the first simpler option.