Cooper came close to the man's face and asked if he liked the "little present" he had got him on Sunday.
The victim believed it was a reference to him being assaulted by two unknown men on that day.
He had 77 hours, Cooper said, to get his friend off the aggravated robbery charge they faced or he would "get him".
After eight months on bail, the defendant doubled his trouble.
Cooper went to his partner's home, where she confronted him about messaging another woman while she had been in hospital following the recent birth of their daughter.
The argument continued to the point where the man grabbed the victim's throat.
She was holding their 1-year-old son at the time.
When the woman tried to call police, Cooper hung up and threw her phone on to the floor.
He then punched her, causing the victim's head to clash with her son's.
"It's just plain cowardly," Judge Emma Smith said.
The woman ran into the bathroom where she was able to successfully call emergency services, but before Cooper fled he issued a chilling threat.
"When you get out of there I'm going to slit your throat," he said.
Counsel Jim Takas said Cooper only had one episode of domestic violence among his criminal history.
While he had previously been a patched member of a gang, he had now given that up to focus on becoming a better father.
He was planning to have his gang tattoos removed once he was released from prison, Takas said.
Judge Smith said Cooper's goal to become a better parent would take more than words and good intentions and Cooper had "a very, very long way to go".
Cooper was jailed for two years and two months.
