A 25-year-old man accused with his girlfriend of causing the death of a five-month-old baby boy has told a jury he had no reason to hurt him.
Eli Cox's mother Katherine Cox, 33, and her boyfriend Danny Shepherd, 25, both deny causing or allowing his death in Kent in April last year.
Mr Shepherd said he saw Eli gasping and gave him adult CPR compressions which he now knew was wrong.
But he told Maidstone Crown Court he was "just trying to save him".
The court had previously heard the baby had 28 fractures and a post-mortem found his death was caused by an injury to his head.
Mr Shepherd said Eli had been grizzly and unwell so he took him upstairs to bed.
He said he laid Eli down in his cot and put a dummy in his mouth, before he popped out of the room for less than a minute.
But he said when he returned, Eli was gasping and changing colour.
"I thought at that point he had something in his throat," he told the court.
Asked by defence barrister Nadine Radford what he did next, Mr Shepherd said he panicked and shouted to mother-of-nine Ms Cox to call an ambulance.
He said he could see Eli was "changing colour".
"I picked him up. He was on my arm at first. I started patting his back. I couldn't tell you how hard," he said.
And he said the other children and Ms Cox came into the room and "everyone was screaming".
Mr Shepherd said: "I put him on the bed and then gave him mouth to mouth. You could see his belly going up but it was staying up, not going down."
'Shock and panic'
Ms Radford put it to Mr Shepherd that the prosecution claimed he lost his temper and either hit Eli's head on a toy or shook him violently.
When asked if he had shaken Eli, Mr Shepherd said: "I couldn't tell you. I was in shock and panicking."
He added: "Personally, I don't think I did."
Later, Mr Shepherd clarified he definitely did not shake the baby.
Ms Radford asked if he had any reason to hurt Eli, and Mr Shepherd replied: "None at all."
The trial continues.