Self-help guru Keith Raniere was a taskmaster who expected his female followers to be as obedient as “hungry dogs”, whether he wanted them to send nude photos to him or buy him groceries paid for out of their own pockets, a former devotee testified on Monday at Raniere’s federal trial in New York.

Lauren Salzman told a Brooklyn jury that as members of a secret master-slave society within an upstate New York group called Nxivm, women were so brainwashed they would jump at all hours whenever asked for “acts of care”.

Among the written instructions for those in the sorority that included TV actor Allison Mack was one stating: “You should be a hungry dog for your master.”

Raniere sometimes ordered them to use a paddle to spank each other as punishment if they disobeyed his rules, Salzman said.

The testimony came in the second week of a trial where lawyers for Raniere have insisted his encounters with the women were consensual and meant to help with their personal growth.

Salzman, 42, took the stand as part of a plea deal in which she admitted to charges accusing her of making a lower-ranking member of the group stay inside a bedroom for two years as a form of discipline.

Mack, best known for her role as the friend of a young Superman in the Smallville series, has also pleaded guilty to participating in the collection of embarrassing material from followers, dubbed “collateral”, which the group threatened to make public if they ever tried to defect and break their silence about their practices. It remains unclear if Mack will testify in Raniere’s trial, which is expected to last six weeks.

Salzman testified that collateral for the group – sometimes called “the vow” – included nude photos with forced smiles that the women took of themselves when they met three times a week in their “sorority house”. Raniere would sometimes demand that they reshoot the photos if they didn’t turn out the way he wanted, she said.

She added: “The elephant in the room was that he was having sex with lots of these people.”

The women were, literally, branded on their bodies as part of an agonizing initiation into the group, but only senior members were allowed to know that the brand represented Raniere’s initials, she said.

When she and others expressed concerns about keeping slaves uninformed about the meaning of the brands, Raniere told them: “It shouldn’t matter” and that “we were making problems”, she said.

The trial continues.