Cameron Bancroft insisted it was his decision to try and alter the condition of the ball during day three of the third Test between Australia and South Africa.
The Australian opener was charged with ball tampering, having been shown appearing to rub the ball with a yellow item on Saturday, which was then returned to his pocket before being dropped down the front of his trousers.
Bancroft appeared to imply he only had a black sunglasses case in his pockets when approached by the on-field officials, but he later admitted he had used tape from his kit.
Speaking at a media conference at the end of the day's play, the 25-year-old revealed he had decided to act after being in the vicinity of a conversation between Australia's senior players.
"We had a discussion during the break, I myself saw on opportunity to get some tape and get some granules from the rough patches on the wicket and try to change the ball condition," he said. "It didn't work.
"I didn't change the ball condition, but I was sighted on the screens and I panicked quite a lot, that resulted in me shoving it down my trousers.
"It was tape. we have this yellow tape in our kit... the sticky side gets very sticky and I felt could be used to collect some stuff from side of the pitch.
"Unfortunately, I was in the wrong place at the wrong time."
When asked whether captain Steve Smith had put him - as an inexperienced member of the squad - under pressure to act, Bancroft insisted that was not the case.
"I don't think in this particular case it was that way, I was in the vicinity of the area when the leadership group were discussing it," he added.
"To be honest with you I was nervous about it because... all the cameras around, there's always a risk. I'm not proud of what's happened at all.
"I've got to live with the consequences and the damage to my own reputation, and do my best to move forward."