Human rights lawyer Peter Madden has travelled to Peru where the two were arrested, and is representing Miss Connolly, 20.
He says the girls were given a camera and told to take pictures of each other as holidaymakers so if stopped by authorities they could convince them they were on tourist trip.
Mr Madden spoke as claims emerged that Ms Reid, 20, from Lenzie, was regularly partying in Ibiza, with neighbours saying she immersed herself in the drug-taking lifestyle of the island.
Both women have maintained their innocence, saying they were forced by a gang at gunpoint to carry 24lb of cocaine worth £1.5 million in their luggage.
They are being detained at a police holding centre and have yet to be formally charged.
Mr Madden said his client, who is Irish, was given strict instructions on what to do and was in fear through the whole process.
"The bizarre aspect of this is that she was instructed to fly to Lima, meet Melissa and then go together to Cuzco [a popular spot for tourists in Peru] posing as tourists so that when they came back to the airport they would be able to show that they were on a tourist trip," he said. "The girls were given a camera and instructed to pose in photographs smiling."
Mr Madden spent seven hours on Friday evening going through Ms Connolly's version of events. He said the plan was to return to Palma with the drugs.
"She was taken at gunpoint, she was tricked into going to an apartment, a gun was produced and put to her head. It was a very, very serious ordeal she describes. She was forced to fly to Palma after threats were made and a copy of her passport was produced as well as photos of her family."
But Spanish police have cast doubt on claims that the two women were forced to carry the drugs.
Sergeant Alberto Arian Barilla, of the Ibiza police unit responsible for countering organised crime, said: "I don't think these two girls were forced to do this because - particularly when you go to South America - you need to pass several controls," he said.
"The first thing you do is go to the passport control and say, 'Listen, this is what is happening to me'. The policeman will react so I don't think they were forced."