But ask him why he did it and it takes a while for him to come up with an answer.
Shields, the deputy rector at King's High School, finished his rugby coaching career at the end of the season, a 38-year spell showing schoolboys the ins and outs of the game.
"I think, as a teacher, it was a good way to get to know the kids. They see another side of you and you see another side of them," Shields said.
"But when I was driving back from Milton after our last game, it sort of started sinking in that that was it. After all those years, I wouldn't be doing it any more.
"The kids haven't really changed over the years. Kids are still keen to play. But there are other changes. I saw a pair of orange boots being worn by one of the kids in a game."
Shields (64) was not one who always insisted on coaching the top sides - in fact, he never coached a first XV.
Brought up in Invercargill and educated at Southland Boys' High School, he started coaching at James Hargest High School in Invercargill, while also teaching English.
He then went overseas before returning to coach at Southland Boys'.
"I got the top under-15 sides and we had Ginge [Paul] Henderson in the team. He was captain, goalkicker and the guy who had the ball all the time. We made it all the way through to an under-15 national final but lost to one of the big Maori schools from the North Island."
Shields continued to coach youngsters at the Southland school before he moved north to King's High School in 1985.
"I started with the Second XV here and they were a bit low in numbers. But Ian Simpson was the principal then and he really invigorated the school."
Shields coached the Second XV with the late Selwyn Inglis, who he described as a coach with a lot of initiative, who never stopped working with the players.
He said coaching a second XV was sometimes tricky.
"You're trying to make a team which sometimes has kids who are a bit disappointed they have not made the firsts or are on their way up. Then, some years, 80% to 90% of the team are seventh-formers who are really good value. It can be really good for you."
After about a decade, he decided to take an under-15 side, and stayed at that level thereafter. He had moved more into managing the team, and assisting the coach when needed.
"They're mainly fourth-formers, with the odd older boy. That last game at Milton, a couple of the older boys held the team together. It looked like we were going to get dealt to. But to see 15-year-olds get stuck in and put their bodies on the line makes you pretty happy.
"Players still want to win. You don't play to participate. You play to win, but then if you don't win, there is always next Saturday."
Rugby was probably not as popular as it once was at the school, he felt, as there were so many options to pick from.
Shields, who will retire at the end of the year, said boys had not changed greatly.
"I do not see a lot of difference in the kids over the years. You have some dreadful training nights and you'll still get a some sort of squad there."
Daryl Shields
Rugby coach-manager
• Age: 64.
• Sport: Rugby.
• Role: Coached junior teams at Southland Boys' High School and Second XV and under-15 teams at King's High School for a combined 38 years.
