The victims, now adults, were emotional as they appeared in court to provide victim impact statements.
The older victim told the court of flashbacks, nightmares and ongoing anxiety which left him unable to eat in restaurants.
"I feel judged about being a sexual abuse victim and don't know who knows it, so it makes me anxious."
He said the man at one time showed him a gun in a cupboard and "I fully believed that he would use it".
The younger victim was too emotional to read his statement which was read to the court by a supporter.
The charges, some of them representative, spanned 10 years.
"I don't forgive him for what he made my life and I hope that I never see him again," the younger victim said.
The man, who cannot be identified for legal reasons, was appearing for sentence on 16 charges: nine for sexual violation, four of sexual conduct with a child, and three of stupefying.
The court heard that the man would disable his victims with amyl nitrate.
Judge Collins acknowledged the strength of character it had taken for the victims to make their statements.
"I admire their courage and in all respects they present as extremely fine young men," the judge said.
The man, who appeared via a video link from Hawke's Bay Regional Prison, was found guilty by a jury trial last year.
Collins said that the man continued to deny his offending, which was his right, but he said that "each and every juror was sure that they [the victims] were telling the truth".
He said this was sustained offending involving multiple acts of sexual violation, with planned premeditation, threats of violence and with a breach of trust of high degree.
The victims, he said, were extremely vulnerable and suffered great harm.
