The sexual act of putting Skittles up your partner's anus and eating them one by one as they come out.
Bob: I just tried a rainbow tunnel with my girlfriend!
Chris: Could you taste the rainbow???
Bob: Among other things...
Chris: Could you taste the rainbow???
Bob: Among other things...
by Redheadedone October 16, 2014
Get the rainbow tunnelmug. by limitededitionpointytoedconverse March 1, 2007
Get the derby tunnelmug. 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. 
A play area style that is a mix of corner camping and aggressive movement. In order to tunnel rat properly, you must move from corner to corner fast. Never sit too long in each corner and don't move too aggressive or you'll fall out of the range of tunnel ratting.
by wolftone1916 March 5, 2021
Get the Tunnel Rattingmug. 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. A tranny tunnel is what you get when a man, in pursuit of becoming a woman, splits his penis like a banana peel and folds it inside out into a wound that constantly tries to close itself.
Alternatively, it is the path for a transmission to be routed.
Alternatively, it is the path for a transmission to be routed.
by RichtersAwful December 4, 2018
Get the tranny tunnelmug.