One of the aspects of XP that also shows up in related styles of development, such as agile, is pair programming.
This is where you work as a team of two, at the same workstation. One of you is the pilot, operating the keyboard. The other is the co-pilot or navigator, and they sit off to the side, observing. Every so often, you switch roles.

Two programmers at work, pair programming. The pilot on the right, at the keyboard, with the navigator to the left. CC BY 2.0
Programmers working as a pair