there is only one rule to pack riding: don't EVER change your path.
This only applies to slow bikes or newbs, otherwise your job is to get as close as possible to everyone without actually touching them. Fingers in buttcracks earn brownie points (get it?), and grabbing people's brake levers or throttles always makes for fun times.
But in all seriousness, avoid the pack. Build a fast bike and learn to ride it, and never deal with the stupid people who can't ride their bike without a 10 foot radius safety bubble. Moped packs are stupidly dangerous, so you always need to have a safe escape route or a plan, and more so you need faith the people around you aren't idiots who bail left or right in a pack of 50 people when they seize. So yea, go fast, its safer that way.