I was wearing my dd in a sling 2 days ago and she was wearing a wool cover. I noticed there was some wicking (probably due to the compression of her being in the sling). DO you guys use wool with your slings or should I use PUL when she's going to be there for a while? Or was my wool maybe not lanolized propelrly? That cover has not been lanolized for about 3 weeks maybe more...