I think they can look sexy as hell on some women, but it depends if they are willing to go all the way for the look. Pick up smoking, wear rough, dark clothes, and it starts taking on an appeal. But if you wear school girl outfits with a nose ring sorry, that's not so hot.
Nope. Trashy boils down to your mannerisms surrounding your personality. I have a few piercing, double nostrils included and I've never had anyone treat me like I'm trashy because of them. Sure some people don't like them or piercings in general, but it all lies on your behaviour not a metal ring.
I had when I was 15, I had 3 piercings now I have one. No, being trashy is related to your behaviour, your looks doesn't make you trashy. Maybe some people who do have some piercings behave in a way that they are considered trashy and I saw some people just want to imitate them by piercing. But when having your genuine behavior a piercing is just something that makes you look a bit different and sometimes cuter.