In Felsen, the way we pray is by chanting "Rock" while holding the ILY ASL sign. Prayer is used for fun and not done in a serious manner to reach god. Prayer can also be used to bless rocks after you paint them to keep them protected.
Any rock is holy and can be painted which makes them more holy. Any paint can be used but not if used to break the 5 principles. Rocks should not look dirty, or be a symbol that harms other or is used to target others.