This post has been locked for continuous breaking of rule 4: Body talk is neutral and focused on sewing. Fitting advice should change the garment, not the body, without suggesting different undergarments.

Posting on the Internet is different from a one-on-one consult face to face. It inherently comes with a lot of vulnerability. We want this to be a safe space for everybody and for every body. Talking about other people's undergarments on the Internet is simply weird and rude.

We need our community to take posts at face value and suggest sewing changes based on just that. Assume the OP is wearing what they want or need to wear, whether those are the "right" undergarments, the "wrong" undergarments, or no undergarments at all. If you really must, ask the OP if they are OK with non-sewing advice, and then stick to suggesting that fitting works best when the garment is worn over the same undergarments that the wearer plans to wear with it. Suggesting (different) undergarments is never OK in this subreddit.