1. What Mr. Happy has (i.e., his "vision" is always focusing on just one thing --- specifically, a gal's "love-tunnel").
2. What the vengeful and intently-gazing-straight-ahead Biff Tannen was experiencing while trying to run down Marty McFly in the underground causeway, and therefore he never noticed Old Man Jones' fertilizer-truck in time to avoid colliding with it --- yet again --- and consequently having himself and his car covered with the truck's messy contents ("MANURE!! I hate MANURE!") a second time, mere hours after having gotten said beloved jalopy back from Terry's garage which had cleaned it out from its previous encounter with said poop-hauler.
2. What the vengeful and intently-gazing-straight-ahead Biff Tannen was experiencing while trying to run down Marty McFly in the underground causeway, and therefore he never noticed Old Man Jones' fertilizer-truck in time to avoid colliding with it --- yet again --- and consequently having himself and his car covered with the truck's messy contents ("MANURE!! I hate MANURE!") a second time, mere hours after having gotten said beloved jalopy back from Terry's garage which had cleaned it out from its previous encounter with said poop-hauler.
I always slow down a bit and drive extra-carefully through mountain-tubes and other underground traffic-passes, since it's notoriously easy to unwittingly get "tunnel vision" when traversing said claustrophobic motoring-routes.
by QuacksO April 7, 2020
Get the tunnel visionmug. The act of putting your dick into the cardboard center of a toilet paper and having your sexual partner arouse you until your dick bursts out of it, or it is bulging around the edges. You then proceed to fuck.
by whydidimakethisshit March 2, 2014
Get the tunnel fuckmug. 
Tunnel sand is a type of sand that a railway/railroad tunnel will produce organically. In the past, tunnel sand has proven to be quite explosive in nature which is triggered by the act of a locomotive entering any tunnel that is producing tunnel sand. Tunnel sand is also the type of sand that is widely used in children's sandboxes in playgrounds.
by letmesubmitanamealready May 19, 2017
Get the Tunnel sandmug. When two guys put their dicks side by side facing opposite ways and interlock their hands and jerk each other off at the same time.
Omg did you see Ron and Don dick tunneling last night? It was seriously one of the hottest things I’ve ever saw. I’m going to be jerking it to that image for a long time.
by Tenaciousron June 6, 2019
Get the Dick Tunnelingmug. by Unicornzzzzzz August 26, 2017
Get the Pixie tunnelmug. by The big mamma t November 12, 2021
Get the Chihuahua Tunnelmug.