On snapchat this means "streaks and recents." Basically, the person is letting you know that they're sending a mass snap to everyone they have a streak with or have snapchatted recently. Can be very annoying if this is all they send you.
"I hate when people send me 's&r,' like, you don't need to let me know that I'm getting a mass snap!"
This is Mrs. Jane Doe from yesterday's meeting about Project 1. I have the information you requested and some follow up questions for you about the upcoming steps. Let me know you're available hours for tomorrow.