I honestly think its somewhat hotter to see a thong panty line under yoga pants. It peaks some interest as to what's hiding underneath. But with or without, if the body looks good in them, I like to see them. I am however slightly confused as to how it would be considered "trashy" to go out in them. I have little knowledge in fashion but I fail to see the difference in wearing leggings or yoga pants in a casual setting, and yet leggings aren't considered trashy? If me and my girl are lounging around the house and decide to hit up the mall for a bit, I don't really see how her keeping the yoga pants on would be trashy. From what she says they're very comfortable so why not? I don't dress up to go out for a casual day, why should she? But that's just my opinion based on my ignorance into the fashion world.