If a team consists of many members, pairs tend to get friendly. Like a courtship. If a pair starts to get along very well, then they prefer to only pick each other.

This leads to specialities and can cause specialization. Example John and Peter always work on the database layer code and get it done really well . Hence the team starts giving all the database tasks to them starting to cause bottlenecks. Everyone who needs database scripts are now waiting for John and peter to get it done.

Promiscuous Pairing is way to avoid this.

Pairs change on a daily basis. Tends to keep the knowledge well spread across the team

A random pair draw at the daily meeting is a way to pick these pairs.

This could cause other effects as developers tend to like some and not like others . Promiscuous Pairing forces the member to get over thier issues and can cause unforseen tensions and a drop in efficiency.

here are some reasons why you should use your own keyboard at all times:)

1) Your pair has a virus ( real kind ) and is sneezing all over the keyboard
2) Your pair had a flu and is recovering from it.
3) Your pair is holding fries in one hand as he./she types and uses the keyboard with the same hand . Umm french fried keyboard.
4) You turn your pairs keyboard on the side and see all the food particles and dandruff fall.
5) Your pair went to the bathroom * enough said:)

If i have convinced you enough carry your own keyboard for pairing sessions and use purell when in doubt:)

An XP practice where two programmers work alongside each other, trying to get a task accomplished. Two minds at one problem.

What does this bring about:

 1) It brings up productivity if the pair knows what it is upto. A chatty pair can cause more damage to the project than getting done

2 ) It keeps each person honest. If you dont know something its apparent in the fifth minute.

3) It helps keep the quality of the code. Since the pair is helping code.

4) This is where design happens.