EOM = end of message. When there is a subject line but no message. It's nice to put it in the subject if you have no message to save people time from clicking and going back.

NQNS = no quit no spit. BBBJNQNS means she keeps going as you are cumming and swallows.

EOM - End Of Message
NQNS - No Quit No Spit

The link takes you to the Self-Help Center.  About 1/2 way down you will find the links to Definitions, Acronyms, Abbreviations, and Terms.  There's other good stuff in there too.  Browse around for a while.

The Urban Dictionary is also a good resource.

you can always use an online urban dictionary to get answers on all sorts of acronyms