This 13 year old kid asks his dad if he can have a bicycle for his Birthday... His father says " Well son...Can your dick touch your a--hole?"
The boy tries it and says "No daddy, sorry"
"Well then you cant have a bike, no get the f--- outta here!"

Next year the same scenario happens...
"Can your dick touch your a--hole?"
"No dad"
"Then get the hell outta my face!|"

Finally, the boy turns 16, and after a lot of hard work and some gymnastics, the boy's dick can touch his a--hole...

"Hey, Dad, how about a car now instead of a bike?"
The dad says "Son, can your dick touch your a--hole?"
Shining with glee, the kid proudly says... "You bet dad! look!" And then he shows his dad expecting a new car...
"Good, then go f--- yourself!"