An unsatisfied morning erection or boner.

Morning wood yearns for some loving, but seldom obtains it.

Until our jobs / classes allow us to swing in 25 minutes late, until we are alone on a business trip and jerk the gerk before our big 8 AM meeting, until our wives and girlfriends value the mean, long lasting hardness that a big old morning glory provides, or allow us to shamelessly whack it at at 6:30 AM while she snoozes beside us, until our kids / roommates pick up 6 AM hobbies far away from our bedrooms...sooooo...sooo much morning wood is unrequited......

When you eat dirt for the first time and leave your family to build a shack in the woods