If you're sent S on snapchat, they are sending streaks. To get streaks to work, send an S every dayback and forth. If they forget to send their S one day you are welcome to scream at them.
“S” probably stands for the word Spermatogenesisicalieperiocladicleesötáans. Well, actually, that isn’t a word, but I uploaded it to the Urban Dictionary and no one voted it to be in it yet god damn it, so do it NOOOOOWWWWWW.........
What you get when you click the Urban Dictionary quick search found in the firefox bookmarks. Check out your bookmark manager, and it'll tell you how to use it, They are just pointing it out to you. If you type "slang " and then whatever you want after the space, it will search that in urban dictionary.