Might I just add some info .... declaring a runway wet or dry can be done from a visual inspection without physically touching the runway surface.... i.e from an adjacent taxiway.
The most common use of this is when changing from dry to wet. When a rain shower/squall has just gone through and it's clearly wet but traffic may be busy and it's blindingly obvious (i.e. the spray thrown up by the last landing a/c
) ...... the transition to dry tends to be slower and more likely to be done through close physical inspection ...
To declare the surface "damp" requires a physical inspection of the surface.
I too have been told the "sit on it" method but the more common usage is to place a hand on the grooved surface and check for cold/clammy/moisture feelings!!