So I've been asked about duets and how to work on them, well I think it's a very simple answer to your question
first:
when singing and you want to do pairing and you don't live near someone that you really want to do a duet with message them and ask if they want to do a duet first
second:
if they agree then record yourself then either post it on youtube, niconico, or mediafire (or anyother download place that you like)
third:
if you really good at editing songs and (if your not i can help with that :D ) then edit the song to sound like a duet or any other thing.
so if you have any questions please contact me at
youtube.com/xakatsukirikux