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. Quantum tunneling refers to the phenomenon in quantum mechanics where a particle has a finite probability of crossing through an energy barrier or potential barrier despite lacking the necessary energy to overcome it based on classical physics. This behavior arises due to the wave-like nature of particles at the quantum level. Quantum tunneling allows particles to "tunnel" through barriers, enabling them to reach regions that would be classically inaccessible.
"In quantum computing, qubits can exploit quantum tunneling to tunnel through energy barriers, facilitating more efficient computation processes."
by F L P May 16, 2023
Get the Quantum Tunnelingmug. 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. Shoving a fleshlight in a man's ass and then fucking them. As to not be gay whilst having fun the the homies.
Jim-"Me and the boys where doing some Tucker Tunnelling last night"
Geoff-"And you didn't invite me?"
Geoff-"And you didn't invite me?"
by TheGasMan69 April 1, 2021
Get the Tucker Tunnellingmug. When there are two mirrors placed in line with each other, and you just see an infinitely long tunnel of mirrors.
by MTGKING456 August 11, 2014
Get the Mirror Tunnelmug. 
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.