This is a technique where two team members work on the same Built (software application) on the same machine. One of the team member will work with the systems(with keyboard and mouse) and another should make notes and scenarios.
It involves the execution of a software component or system to evaluate one or more properties of interest. In general, these properties indicate the extent to which the component or system under test:
meets the requirements that guided its design and development,
responds correctly to all kinds of inputs,
performs its functions within an acceptable time,
is sufficiently usable,
can be installed and run in its intended environments, and
achieves the general result its stakeholders desire.