I managed to not say the word "fuck" until I was 18
In primary school when my friends discovered swearing, I thought "I've never said the f-word before. I'm never going to say it". I wanted to say it when I got older (mostly because my friends would nag me about saying it), but I just didn't want to end the streak of not-saying it
I ended up accidentally saying it to my girlfriend at the time. I said "Someone told me that Ben got with a really fat girl and he titty-fucked her"