"Who's Fishlips Lorenzo?" joke

Giuseppi walks into work, and he says, "Ey, Tony! You know
who's-a George Washington?"
Tony says, "No, Giuseppi, who's-a George Washington?"
He says, "Hah! George-a Washington's the first-a President
of- a United States. I'm-a go to night school, learn all
about-a United States, and become-a U.S.-a citizen."
A couple of days later, Giuseppi walks into work and says.
"Ey, Tony, you know who's-a Abraham Lincoln?"
Tony says, "No, Giuseppi, who's-a Abraham Lincoln?"
He says, "Hah! Abraham-a Lincoln is-a sixteenth President
of-a the United States. I'm-a go to night school, learn all
about-a United States, and become-a U.S.-a citizen."
A guy in the back of the shop yells, "Yo, Giuseppi... you
know who Fishlips Lorenzo is?"
He says, "No. Who's-a Fishlips Lorenzo is?"
The guy yells, "That's the guy who's bangin' your wife while
you're in night school."