Duralex glass tumblers were widely used in UK Schools, so you could enjoy a glass of warm tap water with your school dinner. At the bottom of the glass could be found the word DURALEX, which is mysterious to a child because it has an "X" in it.
More importantly, there was a number at the bottom of the glass. This number was, quite simply, your age - for that dinner hour anyway.
The higher the number, the better. Being 2 or 3 was shameful, of course. However, being 89 was better than being 21 - a display of respecting your elders that would leave the doddering old cunts proud.

After the sexual state of mind had left "girls are revolting poo I don't like handstands", and just before it had reached "wow I am up to my balls in girl" - in that brief period where you were hypnotised by girls doing handstands - then the number on the bottom of a Duralex drinking glass equated to the number of girls you had slept with.
89 was considered respectable. Only having slept with 34 girls at the age of 14 was a sign of severe frigidity, impotence, and (inevitably) gayness.
Girls, never keen to appear the slag, used these numbers to say how many boyfriends they had. Or how many roses their one true love had given them. But never how many dicks they could take simultaneously.
This is what makes men and women are different, and it is why one of them leaves toilet seats up, although I can't remember which. But it's annoying!