Scotch Doubles additional rules:

Played as per the normal game and rules, yet the pair of players take alternate SHOTS each time a ball is played or potted – even at break or when 2 shots are granted. 

if you are on a team with Boris, and you pot a ball, your team’s visit continues, but Boris takes the next shot. You and Boris continue to rotate shots until one player misses. At this point, the other team’s visit begins.

Players MUST alternate with partner.  If not played in turn this will be a foul and 2 shots to the opposing team; with normal foul rules applying . 

Most importantly TALKING / DISCUSSING for team in play is NOT allowed between SHOTS (except after the break). TALKING / DISCUSSING can only be held between VISITS (when playing side changes) or when team is not in play at the table. 

Breaks are to alternate between players, and alternate between teams (break shot does count as a shot) – eg Frame 1: team A, player A.  Frame 2: team B, player A.  Frame 3: team A, player B.  Frame 4: team B, player B. There is no change for any decider frame it just goes in turn.