I think dropping in is different from snaking, almost the opposite. From what I remember, in surfing, when crowded, each wave/big/solid wave allows one surfer at a time to properly enjoy. Dropping in, is when you start surfing when it's someone else's turn. Since you go out to sea to paddle, the person who is at the "front" of the line would be the furthest back from the beaches' POV. Thus when the wave goes to shore the surfer "drops in" when the wave comes and the person in "front" of the line is already surfing behind them(sometimes[perhaps often/every time] forcing them to wipe out/abandon the wave).I thought the term was "drop in"
Snaking is almost the opposite. In that you also start surfing when it's someone else's turn, but you maneuver so you are behind the other person from the beaches' POV. Then it looks like the person you snaked had dropped in.