matted undercoat

Question
My one year old loves water and his undercoat on back hip areas and neck are matted like wool. Help. I have brushed and brushed It does seem to bother him as he is nipping all the time in those areas

Answer
Mats tighten if they get wet, and are that much harder to brush out, perhaps impossible.  You really should take him to a professional groomer to be de-natted correctly, or even clipped if they are beyond salvage, and then have the groomer show you how to brush correctly between visits (which, if you learn brushing technique should be few and far between).  With Aussies, if you only brush on top, you don't get the mats out, and if you don't get them out, they just get worse and worse.  Some dogs have even had maggots get under the mats when the skin starts to break down.  This is a bad situation, and you need to get your pal some help.  Aussies are also prone to "bothering" skin that gets irritated, so you want to prevent that, since it can lead to some nasty infections.  Once you have the coat under control the right way, Aussies are pretty drip dry, and you should be able to allow your furkid to enjoy getting wet again soon.
Good luck!