Pimples "down there"

[athena-altera.livejournal.com]

I am constantly getting pimples between my butt-cheecks, and it is Annoying. They're painful enough as it is, but I have to sit on them too! I cannot figure out why this happens to me. I'm not overweight, I wash every day, I only wear cotton briefs, and I wear skirts every day (never tightly-fitting pants). Does anyone else have this problem?