I don't really hide my purchases, but if I come home with a big bag I'll just walk on through and put it on my sewing table without opening. Then later I'll go get out my new goodies and pet them for a while.
I have a friend, though, who hides her fabric between the mattresses of the bed in her guest room. She says her husband complains when she brings home more fabric, so she avoids that because he never goes in the guest room. Also, in her previous house, there was a storage closet in her garage. She would stash her purchases in there, wait a few days, then get the bags out. When he would ask if she had bought new fabric, she would say, "Nah, I've had this for a while." It was true, she just didn't have to say how long of a while! :)