Evidently not a real sovereign state, however the word is a pun on the suffix "stan", which is common in Muslim areas. Sand nigger is a term used offensively against Arab and/or Muslim people. So it means generically an Arab and/or Muslim country.
"look, if Muslims and Arabs hate Western culture and still live here, shouldn't they go back to sandniggerstan?"
Large natural breasts, commonly defined in slang as "big floppies" or "big ole jugs," but preferably just as "sandifers" for short. Often used as a code word to discuss said big floppies in the presence of others.
Hey man did you see those sandifers? No, where? Heading this way, starboard side!
Pajama casual is a term used when working from home and preparing for a video conference. All business above the waist and your pajama pants down below.