Been able to locate the fact that Bill Caswell did a song in 1983 on Austin City Limits. The song was entitled "Don't Tell Mama", period. A search for copyright info shows that song is his. HOWEVER, the song he wrote is named DTM. The only references I can locate with regard to 'DTMIGP,SJTINJ' and Caswell are here and one other forum site. I think they are two different songs.

I'm gonna keep worrying this song, but that's the way I see it now. It is what Churchill called 'a riddle wrapped in a mystery inside an enigma'.