The most significant problem of a code review is asynchronous ping-pong of quite difficult questions/answers. This is inefficient, but also makes people frustrated.

A session means there is a one driver — one who types/clicks, and one navigator — navigator tells the driver what to do. The 2 other team members keeps attention, and only when the navigator goes in a wrong direction, then interrupts. Navigator navigates for 3 minutes — really, just 3 minutes, and then rotate.