SINGAPORE - Some men would try to touch her during the photo shoots. Others would offer her extra money for "special services".
So when she read online comments that she was taking the easy way out by exploiting her body, Mary was angry.
She said: "You think I enjoy doing this?"
Working as a lingerie model is hardly glamorous, she added. Not when some of the photographers who attend her shoots have questionable intentions.
"There are some who say they are professionals, but when they show up, they use their mobile phone cameras," Mary said. Even the "pros" have their demands.
Posing for them usually means long hours of squatting and bending over for them, she said.
"It's tiring and I sometimes have to rush from one photo shoot to another."
Many of her modelling sessions are held in private studios and small hotel rooms.
She would often find herself in a room with one or two men eagerly snapping away on their cameras at her near-naked body.
Mary said: "I know it can be dangerous, but I'm actually not too worried. If they want to try anything funny, I can always say no."
But a modelling agency director told The New Paper that such dangers are real.
Mr Sasuke Yang, director of Modelz Network, said: "Safety is a big concern for us.
"Before we start a photo shoot, we will do a background check on the photographers in the room to see if they are trustworthy."
He said some photographers are seasoned pros and he is able to trust them with the model.
In the case of others, he would put them in larger groups.