Penises and testicles from donkey, goat, dog, bull and deer, the other contributors to the $200 feast, are laid out on a kitchen table, like a sorry-looking row of odd-sized sausages and veiny, oval vegetables, all waiting to be sliced up by his looming, intimidating cleaver.
"The (horse) texture and the flavour are both very good. It is also good for one's health," said Xiao, who has been preparing male organs since he was 13, using skills handed down in his family for several generations.
Sourced from some of Asia's wildest and most rugged terrains, the organs are chopped up before being arranged on a bed of lettuce around an elaborate glass stand, more akin to something that might display fairy cakes or scones in a high-class cake shop.
The unique dishes at Guolizhuang, China's only penis speciality restaurant chain, are popular among business parties and government officials, Li Yanzhi, manager of the Chaoyang branch, told AFP.
The vast majority of customers are male, she added, many of them searching for increased potency and sexual prowess at the restaurant, which also serves organs from ram, yak, seal and snake -- which have two penises each.
"Chinese people believe we can replenish different parts of our bodies by using the same ingredients, which means whatever you eat is nutritious for that part of your body," said Li.
"Eating penises and testicles can make a man stronger and enjoy a wonderful sex life."
'Potent in bed'
There is no orthodox scientific evidence for such claims, but across Asia there are various versions that come with similar boasts.
In Pakistan's business capital Lahore, Takatak -- a dish whose name is derived from the sound of the clanging knives used to make it -- consists of chopped goat and sheep hearts, brains, kidneys and testes.
"Basically men eat it so that they can be potent in bed," said Faher Hayat, a chef whose roadside restaurant serves the specialty with onions, tomatoes, ginger, pepper and coriander.
"The brains give energy to the head, while the testicles have a power of their own."
On the side of traffic-clogged roads in Jakarta's old town, men looking to improve their sexual performance flock to stalls to drink snake blood.
Customers pick out a snake, which go for 70,000 rupiah ($6) each, before a vendor carefully hauls out the selected serpent, hacks off the head with a meat cleaver and grips the snake's headless body vertically to allow its blood to drip into a teacup or glass.
A spoonful of honey is added to sweeten the bitter mixture, seen not only as a virility booster but also as a remedy for diabetes, high blood pressure and other ailments.
At the Beijing penis restaurant, customer Wei Jingsheng, 47, is a devoted believer.
"It does work very well," said the 47-year-old construction businessman. "After I took it, my hair stopped falling out, and now I feel very energetic the whole day. Before, I needed to sleep at noon to not get tired, now I don't need to. Every aspect of my life has become fantastic."
The restaurant's nutritionist says that its most popular dish is deer, seen as particularly effective due to each breeding male having scores of sexual partners.
"One deer penis has the same potency as three bull penises," said Du Yuemei, who goes to each table to enlighten guests on the supposed health benefits of the dishes and regale them with tales of the animal's vigour in the wild.
With a hint of a smile, she admits to being asked embarrassing questions by some customers, but is immune to attempts to make her feel uncomfortable.
"I know my job is kind of unusual, but it makes me feel good though, that I am involved in dietary therapy for men. It's very unique," she adds, before curtseying and leaving the room, a signal for the waitress to begin placing the ingredients into the boiling soup, made up of deer heart, duck stock and Chinese medicine.
The first to emerge -- steaming hot and the slices slightly shrivelled compared to their earlier appearance -- are the goat and bull penises.
The bull, having curled into a squid-like ring from the heat, had a familiarly beefy flavour, but with a firm texture not easy to swallow.
The goat was tendon-like, rubbery and slightly stringy, like a flavourless, flaccid stick of liquorice.
Both donkey and horse penis were presented in bacon-like strips, but the neutrally flavoured donkey was dark, while the intense, meaty horse was easily the most distinctive ingredient of the meal.
In contrast, the testicles had lighter textures, varying from flaky to somewhere between tofu and pate, and often delicate tastes.
The deer penis was slightly frayed and another rubbery offering, while the wild Russian dog had a spicy, almost zesty flavour, despite looking like slices of undercooked pig-skin.
It was the only imported dish on the menu and the only animal to have a penis bone, ceremonially presented in a red gift box at the end of the meal for good fortune -- albeit not the original owner's.