NY- Good, clean fun didn’t have a prayer at the start of the San Gennaro Festival this year.

Vendors at the Catholic street fair in Little Italy set out X-rated T-shirts that could land them in the confessional for an extended visit.

“Send ’em my way,” said the Rev. Fabian Grifone, pastor of Our Most Precious Blood Church, which houses the statue of the festival’s namesake saint. “I’ll give them a good, strict penance.”

The eye-popping shirts with lewd slogans about breasts, oral sex and passing gas showed up at several stands in Little Italy after the festival opened Thursday.

Jason Schmid, 32, blurted out “Holy s—!” yesterday as soon as he eyed several shirts and men’s briefs that advertised “No rear entry.”

“I’m from New York and I’m used to seeing stuff like this,” Schmid said. “But this is a Catholic festival. What the hell is wrong with people?”

One vendor said his shirts were bringing in big business and amusing the tourists who crowd the annual street fair, which ends Sept. 25. “We had a bunch of old ladies in here giggling,” said the vendor, who asked to be identified only as Paul.

Even as Antonio Tucci chuckled at some of the offerings, he said he felt no need to pay $15 for a shirt advertising an affinity for breasts.

“I’ll just have the girl with me instead of the shirt,” said Tucci, 24, who was with his girlfriend.

Other visitors simply shielded their eyes and moved on to the sausage-and-peppers sandwich booths.

“It’s not appropriate for the festival,” said Len Perry, 58, of Youngstown, Ohio. “It’s not appropriate for the Italian people.”

But the shirts had plenty of fans, too.

“Eh, it’s a free country,” said John Barbaro, 63, of Carbondale, Pa., adding that he was thinking of buying one.

“I don’t think you could wear that in Carbondale,” chimed in his wife, Evelyn, 63. “It’s a small town.”

Festival spokesman Bob Liff said last night that the shirts will go under wraps. Vendors who don’t remove offensive articles will be shut down, he said.