A father and his 10 year old son are in a shop and they walk past the condom section.
The son asks "dad, what are these?"
The father replies "they're condoms son, men use them to have safe sex"
"oh, right" the son replies, with a thinking look
"yeah I've heard about them at school, in sex education"
He picks up a pack of three and asks his father
"Dad, why are there three in this packet?"
His father replies "because they are for secondary school kids. One for friday, one for saturday and one for sunday".
"oh ok" says his son. He then picks up a pack of six and asks
"Why are there 6 in this one?"
His father says "they are for college boys, two for friday, two for saturday and two for sunday"
"Wow! So who uses these?" Asks the son whilst picking up a pack of 12.
With a sigh, his father replies
"They're for married men. One for January, one for February, one for March, and all the way into December"