When you see something so horrific, such as a disgusting girl/guy, it makes you penis want to go back inside of your body. A reverse-boner is rare and the sight you must see to induce a reverse-boner is beyond scarring. You will want to cry when you see the object or human that makes you want a reverse-boner.
Example 1
Guy 1: "Dude did you see Sarah Jessica Parker in her new movie????"
Guy 2: "Yeah bro she gave me a reverse-boner"
Example 2
Guy 1: "Did you go to the hospital yesterday?"
Guy 2: "Yeah a saw your girlfriend changing and i got a furious reverse-boner"
Reverse boner: You catch an old fat guy in your bed masturbating while he eats a fish a jelly sandwich and laughs at you because he hacked your Xbox profile and is ruining your great Call of Duty record. And he killed your newborn and sick kitten with the bone from the chicken that you were going to eat for lunch and is using the fur as a fake mustache.
The phenomenon that occurs when a penis becomes so unaroused that it contracts into an erect, albeit very tiny, state; usually due to the consumption of too much adderall, or a very intense workout.
1. the state a man's penis enters when either the environment gets too cold for its liking, or theres an unnattractive woman in its midst. During this time, the penis will become shorter than usual, resembling a tree stump
2. When the penis secedes from its union with the vagina
a.) Some Guy: gawd its cold here, im getting a reverse-boner...
b.) Some Guy: Dude, i was holding hands with my girlfriend, and getting "You-know-who" (his penis) ready for "you-know-what" (blowjob), but some ugly hoe came along and gave me a reverse-boner!
c.)Some Girl: i was having sex with my bf, but when he was about to stick it in, he had a reverse boner...