Re:
FYI from the PDGA
803.03 Marking the Lie:
A. After each throw, the thrown disc must be left where it came to rest until the lie is established by the placing of a marker. This can be done by placing a mini marker disc on the playing surface between the hole and the disc, directly in line with the hole, on the line of play, touching the thrown disc. A player may instead choose, without touching or repositioning the thrown disc, to use the thrown disc as the marker. The marker may not be moved until the throw is released. A marker inadvertently moved prior to the throw shall be returned to its correct location.