First thing in the morning with a raging Hard-on is a sign of what? Why doesn't this happen when I take a short nap?

Good for you, asking,

Better you should wake up with a raging hard-on than a dead pecker!
What's it a sign of? That you're alive and kicking, that's what! In the average male, testosterone levels fall and rise in tune with his circadian rhythm. Levels are highest from appx 4am to 8am. I guess Mother Nature figured it's best to get her subjects to procreate before breakfast, so that we all can get a head start in the day, LOL.

Hard-ons are fun,
the Love Goddess

Morning wood is a sign that everything functions normally. It happens during REM sleep, which is why you experience it when you sleep. When you nap, you probably don't enter REM. If you want to do research, the proper medical term is Nocturnal Penile Tumescence.

see link

When I was active in competitive sports (only daylight performances, then)I had found that after a particularly intense competition - and being not too banged up - the "repos du guerrier" (warrior's rest) was more rewarding than on a regular day. This was applicable whether the partner was a fellow competitor or a civvie. The morning after with a female ski racer was invariably better (think fireworks) than with a civvie.
Question 1. (born possibly of popular-scientific interest, not to call it curiosity)oes the quite severe training regime and intense concentration needed in comptitive sports alter short-term hormone balances beyond the high adrenaline level needed during competition?
2. Do women (non-athletes) have a circadian "rhythm of horniness" like males have per your post?

Textbook reply, 2ski469,

Young men exhibit a diurnal pattern of testosterone secretion, with a peak at about 08:00 and a nadir at about 20:00. Levels increase after exercise (answer to first question). In women, levels are 5 to 10% of male levels. Yes, women are also affected by their circadian rhythm, with the addition of the modulating effects of estrogen and progesterone (answer to second question.)

Let's hit the slopes,
the Love Goddess