Hi dear,

So Harry says that he and Louis "met in the toilet", so we know that bit is true. This xfactor timeline puts that date as July 21 2010.

I don't have the video of Harry saying that atm, but here is a gif of it. This post also does a great job of summarizing the whole thing.

There are tons of videos of Harry brushing his teeth before performing on stage, so that is another possibility of how/why they met in the toilet. And of course, the line in Sunflower vol 6,

mouthful of toothpaste before I got to know you

which can be a reference to those early days in the xfactor when they were still getting to know each other, but were living together and possibly brushing their teeth together in the same shared bathroom. It can also be a reference to the first time they met, and Harry could have been brushing his teeth then.

We won't ever know for sure, but either theory works imo. And I think the bottom line is Harry's reference in his lyrics - they were getting to know each other and living together at the same time, but they fell for each other pretty instantly. So picture these teenagers who are absolutely into each other, flirting, having all these new experiences. One of which is living in the same "dorm/flat" as your crush, and you get to have a moment every night of going in the bathroom and brushing your teeth together. I think it perfectly encompasses that lyric in Sunflower vol 6.

Harry sings:

Sunflower, My eyes, want you more than a melody, Let me inside, Wish I could get to know you

all of that speaks to that feeling of knowing you're falling in love, of being so into someone you want them more than anything.

Then he sings:

Wondering headshake Tired eyes are the death of me Mouthful of toothpaste Before I got to know you

Which again can be linked to them living together at the xfactor house, and he talks about Louis' "tired eyes", which can reference waking up together or how his eyes often look like. As well as the toothpaste line, which I discussed above.