The player who has scored 41 tries in 56 internationals said he is going to go looking for the ball so that he can enjoy playing the game the way he likes to - with the ball in hand.
Speaking at the Wales squad's Cape Town base he said: "I've come here to play some rugby and enjoy myself and I'm going to try to get my hands on the ball as much as possible.
"I prefer to play on the hardest grounds possible. It helps the player who is fleet of foot so hopefully it will help me.
"Hopefully the game will be a lot wider and a little bit more open here.
"I'm really enjoying my rugby at the moment. It's been a big year and it's not over yet. It's just possible we have the hardest job of the year coming up."
But the flying wing admitted there is now intense pressure for places in the Welsh team and he is aware that young players are contesting for selection.
He said: "I've got to watch myself because we've got Tom James and Jamie Roberts of the Blues putting their hands up at the moment. They want to play for Wales.
"We've also got a few scrum halves putting their hands up out here as well.
"As a squad we are very confident. We have got a couple of lads out injured but that's what happens at the end of a big year. Certainly we have got strength in depth at the moment."
Williams is now one of the senior players in the Wales squad and said he is under no illusions of the size of the task ahead when the Grand Slam RBS 6 Nations champions face the World Champions.
He said: "We have come out here and we know that we are probably going to have to play better than we did to win the Six Nations."
He went on to praise the way the new coaching team under head coach Warren Gatland has brought a new rigour to the preparations of the Wales team.
"Warren places a big emphasis on the intensity of training and taking that intensity from training into the games. So basically we work hard, hopefully harder than the teams we are going to play."
Gatland echoed Shane's wish for a fast game against the Springboks so that his Wales team can learn to perform under pressure.
He is pleased that the South Africa coach Peter de Villiers was talking about playing an open style of rugby against Wales.
Gatland said: "I noted that Peter spoke about placing a strong emphasis on the off-load and going out to run us off our feet," he said.
"That will be good for us if it happens because it will place us under pressure and the more pressure we are under the better, because we are here to learn."