I've used bumgenius pocket nappies since the start and they've been great but now ds is 9months and crawling they are rubbing on the inside of his thighs making them red and dry. It doesn't seem to be painful for him at the moment but I'm now using disposables during the day. Is there anything I can do to stop the rubbing? It seems like a major design flaw unless I'm just doing something wrong or his skin is particularly sensitive?