Samoans seem to be very body-part-conscious.
You might call it modest or reserved maybe, but all my training in 'behaving so my mom, aunts and older cousins don't give me the evils' seemed to have a lot to do with how I positioned my body in specific situations.
Now that I'm grown, I see the wisdom and the respect behind the Samoan way of carrying oneself. The learning is so instilled in me, it even gets a little offensive when someone (inadvertently or otherwise) breaks one of the following, um... guidelines? around me.
Passing in front of people
Especially when people are seated, if you have to move in front of them to get somewhere, you MUST excuse yourself. In Samoan, the word is 'tulou' (excuse me).
You should also try to stay low. For example, if you are passing between two people who are standing, you should should bow down as you move (and excuse yourself), so that you don't obstruct their view of each other.
And you thought you already knew how to sit.
If you're sitting on the floor, omg fold your legs! (making sure, of course, that all your 'bits' are covered up properly).
It's very rude to extend your legs so that the bottoms of your feet show to anyone else in the room. If for some reason you can't fold your legs, then tuck them under you somehow.
Oh, and never ever draw your knees up to your chin while you're sitting (you know, like when you're hugging your legs) unless all your business is covered up properly. If you're sitting amongst a group of elders, just don't do it at all.
Sitting on a chair? It's all universal common sense. Just keep your knees together unless they're covered up properly.
Standing while people are sitting
The only time you should be standing in an area where a group of people are sitting is if you're taking yourself out of that area or you're serving them (in which case the guideline above about excusing yourself would apply).
If you need to speak with someone who is sitting, especially if this person is older than you, you need to bring yourself down physically to their level. Just sit or crouch down so that you're at eye level or lower.
It's just wrong for them to be eye level with your stomach or somewhere worse while you're beseeching their attention.
Legs and Pants
Pants are not in the traditional Samoan wardrobe, so even in the modern world, we're mindful of how they're worn.
For ladies, if you're going to be at a gathering of Samoans (i.e. family) and happen to be in pants, don't be surprised if someone hands you an ie lavalava to wear over them, especially if you're going to be walking around amongst others (i.e. serving tea, etc.).
For men, pants are more acceptable of course, but for formal occasions and cultural-type gatherings, it's always better to see them in ie lavalava or ie faitaga (the more dressy version of ie lavalava, that usually includes pockets)
Boobage and lavalavas
This one kind of surprised me. You always see images of islander women in ie lavalava wrapped high, up under their arms and over their breasts. I guess that's okay for other Pacific islanders, but for Samoans, not so much.
I was taught that my ie should be worn around my waist only (with a shirt or something to cover my top half, obviously). Wearing it the other way (up under my arms) should be reserved for the privacy of your own home / shower / husband.
I'm not sure what the reasoning is behind that. Maybe someone can enlighten me (in a comment below).
Other guidelines about minding your body parts include not sticking your elbows in people's faces when you're passing an object to someone near them and not wearing bikinis / speedos when you're swimming in public (Samoans wear shorts and tee-shirts or even jump in fully clothed. Seriously).
I think, though, that if you have the attitude that your body is sacred and so is everyone else's, the Samoan way of positioning your body in social situations should make a lot of sense to you.
I would hope so, anyway.