The hall was adorned with dimly lit candles, soft ambient music, heart-shaped plates and meerkat stuffed animals sporting pink elephant thongs and dollar bills.

Fellow zoo keepers thought Jane Tollini had gone mad when, almost 20 years ago, she placed red hearts and a boom box playing Johnny Mathis near the penguins’ ice pond to set the mood for Valentine’s Day. They couldn’t see her vision: foreplay, ménage à trois, and what she called “bow-chick-a-wow-wow.”

“What can I say, I like to watch,” said Tollini.

For two years, the male penguins gathered the hearts that Tollini had dispersed and started decorating their mates' birthing dens. The crowds of onlookers grew.

Eighteen years later, her concept has been expanded into “Woo at the Zoo,” a 90-minute sex tour held in the San Francisco Zoo’s Great Osher Hall. Tickets are $70 for each guest, which includes an indoor multimedia presentation, up-close animal encounters and romantic refreshments including champagne, risotto, sushi and chocolate-covered strawberries.

Tollini, who has been the zoo's penguin keeper for 24 years, first developed the idea when she noticed penguins were incredibly amorous around February.

She started recognizing other things around the zoo — things that made her say “whoa nelly!”

Despite common belief, the animals will not "mate on cue" during the 21 and over event. But guests should be prepared to learn the un-rated version of the birds and the bees.

“It’s about how far, how deep, how wide, and how many,” said Tollini, who described everything from polygamy, bondage, bisexuality and forward dismounts among the animals.

“[The tour is] tasteless, tacky, gritty, and smutty—but it’s all true,” she said.

Starting off with animal penises, Tollini moved on to vaginas, including ones so large “you can lose the entire family and the family car in.”

Then, she followed with details on cockroach Kama Sutra, millipede “wet kisses,” hermaphrodite banana slugs and nympho-birds.

“You can expect everything from soup to nuts,” she said about the tour.

During the presentation, animals were showcased one-by-one inside the Great Hall. The animals included an armadillo, porcupine, eagle, bunny, snake, tortoise, hedgehog and an opossum—a creature that has two uteri, “so it can get pregnant, while it’s pregnant!” Tollini said.

At one point in the evening, she even brought out a toad and kissed it, with hopes it would turn into her prince: Antonio Banderras.

Attendees mostly ranged from their 20s to 50s, but some appeared to be in their 60s and 70s. Regardless of age, the room was filled with couples.

John Shilkaitis had reserved tickets three months in advance for him and his girlfriend.

“It was awesome,” Shilkaitis said, “it was very foreword and entertaining, with very open sexual humor.”

After the presentation, attendees were able to walk and meet some of the zookeepers, many were student interns for the Koret Animal Resource Center (ARC), a program that offers hands-on work experience to people interested in a career in the zoological field.

Elaine Chu, 23, SF State senior environmental studies major and wildlife night’s guide, noticed that many of the couples became more relaxed and very affectionate as the night went on.

“They are probably going to go home and do it like cheetahs,” laughed Chu.

Kevin Fagundez of San Mateo, 28, said he had no idea what to expect.

“When the penis talk started, I was nervous,” said Fagundez. “My date had such a surprised look on her face.”

But by the end of the night, the two were holding hands and sharing chocolate-covered strawberries.

“It gives people education out of the classroom, a side of zoology they never knew,” said Christina Maillard, 24, a UC Davis graduate and ARC Intern.

According to zoo spokesman Paul Garcia, there is a maximum of 80 attendees, so advance purchases and reservations are required, as this event sells out every year.

"It’s a great date night for those in their 20s looking for something different,” said Garcia.

Information and tickets can be found online at http://www.sfzoo.org.