The same original
meaning as "rode hard and put up wet
" in that it was originally used in refrence to a horse which was not cleaned and brushed after taking a ride.
The phrase is now used as a way to descride a slut
in that she was rode hard (fucked
) and put to bed wet (wanting more, wet as in horny).
"Look at that slut, Sally. She has been rode hard and put to bed wet."