Glad to find this thread. This very morning, as I was standing over the bowl taking my morning pee, I paused to wonder if I was unique in my experience of regularly having 'morning wood' at my age (almost 40). I agree with more than one of the posters here in that it usually occurs when I wake up without the assistance of an alarm clock and that it is not usually because of a full bladder. I will add that I usually take the opportunity to do a few sets of kegel exercises while I'm lying on my back in bed!