Using soft modification tool
 

Does anyone know the keyboard short cut to adjust the brush size of the soft mod tool? I can't figure it out and the default size is only moving one verticie at a time. I know it's possible, because I've seen someone do it, when he was explaining it to me, unfortunately, his hand moved way too fast over the key board for me to pick up on which key he hit.

Hold down the `b` key and left click drag left or right.