Pair testing is a software development technique in which two team members work together at one keyboard to test the software application.
[1] This can be more related to pair programming and exploratory testing of agile software development where two team members are sitting together to test the software application.
Developer can find out which portion of the source code is affected by the bug.
This track can help to make the solid test cases and narrowing the problem for the next time.
This follows the same principles of pair programming; the two team members should be in the same level.