It's 7pm on a Friday and there are 42 sets of eyes fixed on the naked man, the eyes of women who will, over the next couple of hours and with the aid of three artists-instructors, paint the man on the canvases on easels in front of them.
The quality of these paintings will vary widely but "I have been really surprised by how well some of them do", says Jonathan Miller who, a few minutes before he takes off his clothes to pose, admits: "The first time I did this was nerve-wracking. But now, after doing it 15, 20 times, it's a lot easier. I am just being part of a fun evening in a creative and light-hearted place."
The women at the class, at the Bottle & Bottega painting studio in Chicago's Lakeview neighbourhood, are a lively mix, most under 40 and of all ethnicities. Six women are part of a 30th birthday party; a dozen part of a bachelorette party; a few groups of women not part of any celebrations but simply looking for, as one says: "Something out of the let's-all-do-shots ordinary bar stuff."
None will give their names, their reasons varying along the lines of "my boyfriend doesn't know I'm here", showing people can still be uncomfortable talking about sex and sexuality, and public nudity.
Yet naked bodies have been the stuff of art since cave drawings, and almost every museum in the world features representations of the unclothed human form. "Man's naked form belongs to no particular moment in history; it is eternal, and can be looked upon with joy by the people of all ages," French sculptor Auguste Rodin said.
But most others aren't as worldly. "Sometimes women will paint underpants on the painting of my body. I don't wear underpants when posing," Miller says.