Mr Bolletta could stretch the muscles "rather painfully".
"I have called him some names that are not what zen-type yoga people might use ... but the after-effect is worth some of the pain he puts me through," Mr Watson said.
He said Mr Bolletta "is pretty special" at his expertise and "so he's coming to St Moritz" with the family for two weeks soon.
Mr Watson, his wife and four sons are frequent flyers, jetting in private planes between their homes across Europe and the Atlantic.
"I haven't quite found anyone as good as [Mr Bolletta] is," Mr Watson said. "I'm a bit concerned too about advertising his skills in the newspaper ... because the price I'm getting him at is very competitive and I don't want [it] to go up.
"We've got a contra deal. He's going to stop me from injuring myself from skiing and I'm going to help him to injure himself while skiing.
"I'm going to teach him to ski, for sure. He'll be starting up right at the top of the mountain ... I'll introduce him to skiing the same way he introduced me to stretching ... it's going to be a very big day."
He said Mr Bolletta had managed "to put me into various yoga positions that I could never accomplish on my own" and that he looks all of his 55 years thanks to not having taken up yoga earlier. He said his wife had been doing it for many years "and is quite proficient and very good at it".
Mr Bolletta, 47, won't say how much he's earning, but "it's a good wage".
He lives in Parnell with his yoga-teaching wife and their two young children. He does yoga teacher training at the Kawai Purapura centre in Auckland, runs yoga retreats overseas and in the South Island and teaches in China.
Initially, Mr Watson was not convinced about yoga so Mr Bolletta said he called it "stretching" instead.
He said of Watson: "He's witty, smart and committed to his health, which is good. He works hard."
Yoga is rising in popularity. An annual four-day yoga festival, Wanderlust, attracted 4000 people in Taupo last month.