Having started dating his current girlfriend, everyone could not remember the code from the home phone of her entrance, so he constantly called her and asked him to remind her. At some point she got tired of it:
Let’s come up with a mnemonic rule. My code is 23v1369. 23 – because I’ll always be 23, and it’s best for you to fuck me at that age, not at 13 (because they’ll be planted), and not at 69 (because it’s perverted).

I remember from the first time and now every time I type the code, I smile.