Here are some awesome dirty knock knock jokes for boys.
1. Knock knock!
Who's there?
Madame.
Madame who?
Madame foot's caught in the door!
2. Knock knock!
Who's there?
Dwayne.
Dwayne who?
Dwayne the bathtub, I'm drowning!
3. Knock knock!
Who's there?
Little old lady.
Little old lady who?
I didn't know you could yodel!
4. Knock knock!
Who's there?
Banana.
Banana who?
Banana split so ice creamed!
5. Knock knock!
Who's there?
Water.
Water who?
Water way to answer the door!
