This paper discusses two-handed input for interaction with notebooks, motivated by the observation that notebooks are often used with an external mouse. We present results of a survey of 905 notebook users, of which 63.8% reported occasional, and 47.0% regular use of a mouse instead of the built-in pointing device (a touchpad in 95.8% of the reported configurations). Based on this finding, we propose use of the built-in touchpad with the non-dominant hand when an external mouse is used as primary pointing device. We provide a systematic analysis of the input space of such a configuration, and contribute a set of techniques that specifically exploit touchpad properties for input with the non-dominant hand. These techniques include flick, scale and rotate gestures; absolute positioning with tokens; and touchpad use as key modifier. The techniques are demonstrated in a variety of GUI applications in a standard environment of notebook with external mouse.