Clare: All I can think of is a tunnel, like when you’re on a train and the light at the end of it. But, I can’t think of why someone would need a slang version of it? Maybe it’s just another word for “idiot”?
Isha: This sounds extremely kinky and I feel like we’ve ventured into Fifty Shades Of Grey territory. So, considering that, I’m going to say some sort of sex toy.
Jules: No clue, so let’s take a punt and say it’s when someone is narrow-minded. Example; “OMG, can’t stand Jason, he’s so tubelight.” Like, he can’t see ALL the light, he can only see it through a tube. Yeah, I’m into this. Let’s make this a thing.
Actual Meaning: Someone who takes a long time to understand jokes or things in general. This is because when you switch on a tubelight it flashes only after several seconds.
Example: "Suppandi is such a tubelight, he got the meaning of the joke after an entire hour!"