An erection that occurs when a man becomes tired, but is fighting hard to stay awake. Instinct boners often occur during boring lectures or when driving late at night and will not go away as long as the urge to sleep persists.

Origin: In order to protect their food supplies and sleeping families from scavengers, early humans evolved the process of instinct boners by frequently masturbating to stay alert while on cave watching duty.

When ones penis is no longer erect, possibly either after blowing ones load, or just losing an erection. A semi-boner is often used for playfully slapping ones friends in the face while they sleep for a hilariously good time.

A little wiener shaped creature with wings that fly's through the night and gives people random erections while they sleep. Due to high volume of night time boners, the Boner Fairy is said to be quick a swift with her work, and seldom is spotted, and never is caught.

A boner aquired while sleeping. A sleep boner.

A great song by the Whitest Kids U' Know singing about how hard, how weird, and what you must never do with a boner, including, but not limited to: Trimming the hedges (with the hedge trimmer pointed down).

An erection that occurs in the morning and is naturally caused as the brains enters the REM-deep sleep phase. At this stage, the body's skeletal muscle structure relaxes and causes hypervasodilation in the capillaries of the body, resulting in said erection.

The erect penis of a sleeping male. Such named because someone sleeping with said male may get repeated poked with said erect penis as the male moves in his sleep, resulting in a feeling of getting attacked by a very small shark.