I decided a year ago to try to avoid underwear and all crotch abrasion. The Commandos (below) didn't do it for me (although still worth a try for someone else). The surface feels a bit like felt and I don't think that is vulva-happy. Silk satin, please! Hmm. What if I used a spray-on fabric glue to attach silk fabric to the crotch over the felt? I still like the overall concept of Commandos and they adhere really well.
My wardrobe (other than for exercise) currently is all skirts and the beloved overalls.
I've noticed that any touch - clothing or husband or myself - will give me a flare in pain that last for four days.
No more underwear! Commandos are meant to be adhered to the crotch of your pants in order to avoid wearing underwear. They cost about $20 dollars per pack of 8 - expensive to me. If you are willing, they will stay on a given pair of paints securely for for multiple wearings.
The good: no cutting into your inner thighs like most underwear does, the surface is of a non-irritating material and is certainly better feeling than a pantyliner, and it adheres very well to the crotch of your pants.
The bad: if you have vestibulitis, you will still have contact irritation, although it may be lower.
My vestibule is extra-unhappy right now. I haven't worn underwear since July when my vestibule and clitoral hood went crashing into severe unhappiness.
My underwear alternative when I can't deal with my normal underwear is either 1. nothing, or 2. baggy, short pajama bottoms from the Gap (the best place to find them). I buy XL to get the crotch low enough and wear them under skirts and overalls (a favorite clothing item because of baggy crotch).
P.S. Would it be a helpful article if I wrote about sewing to lower the crotch of your pants? I do this routinely. Let me know.