Little Johnny walked into class with a black eye. The teacher was concerned and asked, "What's wrong?"
"Our house is very small. Me, my mum and my dad all sleep on the same bed. Last night my dad asked, 'Johnny are you sleeping?' When I said 'No', he slapped my face and gave me a black eye."
The teacher said, "The next time your dad asks if you're sleeping, keep dead quiet and don't answer."
The following morning Johnny came back with two black eyes.
The teacher, by now very worried, asked, "My god, why have you now got two black eyes? I thought I told you to say nothing."
Johnny replied, "Dad asked me again, 'Johnny are you sleeping?' and I shut up and kept dead still. Then my dad and my mum started moving, you know, at the same time, and mum was breathing erratically, kicking her legs up frantically and squealing like a hyena on the bed. Then my dad asked my mum, 'Are you coming?' Mum said, 'Yes I'm coming, are you coming too?' Dad answered, 'Yes!'
They don't usually go anywhere without me so I said, "Wait for me, I'm coming too ..."'