Ships have to still be "touching" when the ships activate in combat for the touching rule to stop an attack.  So in your example, your PS2 ship bumps his PS6 ship causing you to be touching.  Then the PS6 ship moves -- if it manages to move off of you (it's not "touching" you after the maneuver), then you two are able to shoot each other during combat because you've stopped touching.

Touching, as a game rules term, happens when your final position overlaps, and you have to back up along your template to find a valid location.  The ship or ships your base is touching after backing up are the ships you are touching.  Touching remains in force until one of you changes position again

Repositioning can be from their next maneuver, or can happen even from a barrel roll or boost, e.g. Turr shoots past you to hit a different foe, then uses his ability to barrel roll away.  Or if an ally with Coordinate or Squad Leader gives a bumped ship an action.  But in general, if a higher-PS ship slams into a lower-ps ship, it's there for the rest of the round.

Trivia: The "Zeb" crew can allow you to shoot someone you're touching, and they can shoot you.  ^_^

One last thing -- as the lower-PS pilot, keep in mind that "blocking" is a useful tactic.  Blocking means deliberately moving your low-PS ship where you think an opponent will land, causing them to bump into you.  There's several advantages: as above, they won't be able to shoot the blocking ship (though they can still shoot other ships).  Bumping causes them to miss their action step, so they can't reposition, token up, etc without help from an ability that grants actions.  And last of all, they might not be as far forward as they expect, causing them to land on a rock, or in a "kill zone" where all your ships' arcs are on them and they're relatively defenseless (without their tokens etc).  So it's a devious tactic that's worth having in mind.

Higher-PS ships have quite a few advantages of their own, but blocking is one of low-PS's characteristic advantages.

Thank you! this was insanely helpful! definitely coming back here if i have more questions rather than diving through the internet looking for a semi-compitant answer lol. i even showed my dad the rule in the rulebook and he still said i was wrong lmao friggin scrub XD. but again thanks a bunch!

FFG's rules can be pretty hard to parse out at times and there are some important subtleties, so it can help a lot to just come ask the experts when something is confusing.  We're happy to help here!

There's also a rules forum on FFG's Website (as well as other forums like squad building).  Lots more people there and they're often quick with answers, though occasionally they're rude (or they spend pages arguing with each other and dancing around the original question -- hah!).  It's just a different culture; they can be a very useful resource in a lot of ways.

While I'm sending resources your way, also check out the Squad Builder.  There's many of these, but IMO I've found YAML to be the best and most up to date.

If you need anything, feel free to ask here.  We're very happy to answer questions or provide suggestions.