John Schudlo, who calls himself a "work friend" of Sona's, is telling court he heard how voters in Guelph, Ont., received automated telephone calls on election day.
Schudlo says Sona told him at least one accomplice helped with the scheme to use a disposable cellphone and an online autodialing service to make automated calls intended to misdirect non-Conservative voters.
On Wednesday, Schudlo's colleague Rebecca Dockstaeder described hearing the same conversation, but recalled Sona saying he executed the scheme by himself.
Sona, who worked on the local Conservative campaign in Guelph in 2011, is charged with "wilfully preventing or endeavouring to prevent an elector from voting."
More than 6,700 phone numbers received automated phone calls falsely claiming to be from Elections Canada that contained incorrect information about where to vote in Guelph.
Both Schudlo and Dockstaeder testified that they weren't sure they believed the story at first, saying Sona was prone to exaggeration.
"My impression was he was sort of revelling in it, it gave him a bad boy vibe, I guess," Schudlo testified.
"Mike is a storyteller, and I'm giving him credit in a way, he tells an interesting story…. It just seems sometimes over the top."
Schudlo said he was initially hesitant to speak out, and only did so when Dockstaeder insisted they should.
"This is not a fun experience for me, it's been quite stress-inducing," he said, adding that he felt it was his duty to corrorbate Dockstaeder's story since he was there.
"I feel like I've lost a centimetre off my hairline."