There's a technique called double dealing that sounds very similar to what you are describing, found in Expert Card Technique. Other than that I'm not sure what you're talking about unless you post a video or a more in depth description.
I believe what you're describing is similar to Harry Lorrayne's HaLo cut but just done with a small packet. I use it in a trick that i do but i'm unsure on the actual name of the move. I've always called it the HaLo Count simply because of the similaraties between the two moves.