[OS X TeX] Handling punctuation and spaces after an abbreviation

[Nirav S]

In my writing I need to use the abbreviation SoS -- not the distress signal -- it stands for system of systems.  Some people prefer this typeset as "SoS" or "SofS" or "S-o-S" or one of these in italics.  To deal with this, I created a macro:

\def\SoS{SoS}

which I then change depending upon the convention being used in the particular paper.

My problem is that this macro doesn't work well it the middle of sentence, i.e.,

I really like \SoS.  typesets as "I really like SoS."

while

\SoS are my favorite things. typesets as "SoSare my favorite things."

Changing that to "\SoS\ are..." makes it so that 'SoS' and 'are' don't run together, but then "\SoS\," makes the comma disappear.

What's the correct way to do this?  Right now, I'm making lots of mistake trying to remember whether to type \SoS\ or just \SoS depending on the punctuation (or lack thereof) that follows.

Thanks!

 - Nirav