From: utzoo!decvax!harpo!npoiv!alice!rabbit!ark
Newsgroups: net.nlang
Title: Re: posslq
Article-I.D.: rabbit.1112
Posted: Tue Feb  8 18:01:44 1983
Received: Fri Feb 11 05:18:05 1983
References: hou5e.189

I think the term was coined by Infernal Revenue.
It is an acronym:

	persons of opposite sex sharing living quarters