This touchpad has pads which do a good job at keeping it in one place when used on a table or desk. It isn't designed to be placed on a mousemat which typically have a surface designed to allow a mouse to glide smoothly over it. How well it would stay still would depend on the mousemat's surface. This is supposed to be a replacement pointing device (although both the touchpad and a mouse can be attached and used simultaneously). I'd suggest the touchpad is placed on the desk top one side of the mouse rather than on top of it.