I am going to ask a really silly question: Have you tried using a panty liner? (yes, the period product!) They tend to make panties a little more structured while still allowing for natural movement, and I assume it will help with a gaff too

These kids are really young, I mean where does an eight year old get the idea and motivation to do this? The twelve year old probably egged the others on, but still this is such an intense crime for such young ages