Jos Buttler said "red mist" was to blame for his sweary outburst at Vernon Philander, though he has questioned the use of stump mics being turned up in cricket.
England's wicketkeeper-batsman was fined 15 per cent of his match fee after stump mics picked up his expletive-laden rant at Philander, who appeared to peeve Buttler by not moving when a throw came in from a fielder.
The incident occurred on a tense fifth and final day at Newlands, when the tourists eventually got the wickets they needed to seal a 189-run victory inside the last hour.
Buttler noted the situation was a factor in his comments, but admitted they were unacceptable.
"I'd like to apologise, I understand that's not the way to behave," he told BBC's Test Match Special.
"As role models we have a duty to behave in a certain way.
"In Test cricket there are lots of high emotions at times and things can be said that don't necessarily mean anything, but for viewers at home it can come across very poorly.
"Sometimes it's just one of those things, the heat of the moment and a bit of red mist.
"It's all done so hopefully it can be swept under the carpet and we move on. I'll take the slap on the wrists."
However, Buttler hinted that players would prefer stump mics not to be turned up so such incidents could remain between those out on the field.
"It's a tough one," he added.
"We understand it adds to the viewership experience having stump mics and being able to hear what goes on, but we also like that what goes on the field, stays on the field and isn't necessarily heard by everyone at home.
"I'm sure it's up for debate."
England's win meant the best-of-four-match series is level at 1-1 ahead of the third Test, which begins in Port Elizabeth on Thursday.
An illness bug has hindered the tourists throughout their time in South Africa and captain Joe Root was the latest to miss training on Sunday.
"It's obviously a frustration, nobody will miss being at training more than Joe," Buttler said.
"It's been a bit of a story of the tour so far, guys getting ill, but I'm sure he'll be fine. Hopefully it's just today."