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 bedwet."
to perform a vigorous sexual thrashing on someone, causing them to sleep for an unspecified amount of time, sometimes resulting in some short term memory loss.
"I wanna put my fingers thru your hair Wrap me up in your legs
And love you till your eyes roll back
I'm tryin to put you to bed..."---"bed" by J. Holiday