Mystical Arousal

An hour or so ago, I awoke from my usual morning nap...and my nipples were hard and erect, almost as if someone had been playing with them or even sucking on them. Naturally, this had me feeling very aroused....and quite confused, because I had no idea what could have caused this. I do not remember having had an erotic dream (the usual cause of such arousal) and I certainly wasn't playing with myself in my sleep...or at least I don't think I was....