He hears his mom call his dad a bastard and hears his dad call his mom a bitch.

He asks, "Mommy, what does bastard mean?"
The mother answers, "Um, it means boy."

Then he asks, "Daddy, what does bitch mean?"
The father says, "Uh, it means girl."

Later that day, the boy sees his father in the bathroom shaving; the dad accidentally cuts himself and says, "Sh*t."

The son asks, "What does "Sh*t" mean?"
The dad says, "It means shaving cream."

Then he sees his mom in the kitchen carving the turkey; she accidentally cuts herself and says, "F*ck."
The son asks his mother what does "F*ck" mean and she says, "It means carving."

That evening, the family's guests arrive for Thanksgiving dinner.

The son opens the door to welcome them and says,

"Welcome Bitches and Bastards!
My dad is in the bathroom rubbing sh*t on his face
and my mom is in the kitchen f*cking the turkey."