The arresting officers also noted a scratch to his neck and marks on his arms and legs when he was arrested.
A coronial inquest held in February heard that a post-mortem examination found Chipchase died from "pressure to the neck".
Tenniswood, 52, denies the allegations and claims Chipchase had died from a "dreadful accident" in his apartment after falling backwards while attempting to sit on his sofa.
He sustained a scratch during the fall, he recalled. Afterwards, they laughed about the slip and, soon after, Chipchase gave him a French kiss.
He said the pair engaged in "vigorous lovemaking" with Chipchase, before demonstrating to jurors the moment Ms Chipchase allegedly placed Tenniswood's hands on her neck during sex.
"She puts her hands on top of my hands and moves my hands down to her neck," he told Birmingham Crown Court in the witness box as he placed his own hands around his neck in a rubbing motion.
"It's a very organic thing."
He alleged she then moved his hands away, but allowed him extra time during a second attempt.
Tenniswood detailed how he applied pressure to her neck for up to 10 seconds, where "her body spasmed and she let out this extraordinary exhale".
Tenniswood then "effectively blacked out" before he "cuddled up" to her dead body, apparently unaware she was unconscious.
He told the court the pair had sex twice and the victim had not felt that happy "in ages".
When he found Chipchase unresponsive the next day, he thought she was in a "diabetic coma" or had suffered a "stroke or brain injury" throughout the night.
"I said, 'India, darling?' I just went over and looked at her. It just didn't seem right. I just sort of nudged her shoulder."
When he realised she was unconscious, Mr Tenniswood said that instead of checking her pulse, he said he downed a drink of wine
"I decided not to do that on the grounds I'd never taken one before," he said.
"I thought, 'What is that going to do?' Is that going to upset me even more or answer any questions?'
"I ruled out feeling the pulse, and returned to have another swig of wine.
"Panic set in" and he had to leave the apartment to "get some air, get food, and calm down".
But before he left, he re-dressed Chipchase in order to be "respectful" and changed his mattress, which was bloodstained from a head injury suffered by the victim.
"I was absolutely convinced she would gain consciousness while I was out," he said.
"I went to get a kebab, get something to eat. What had been a glorious evening suddenly turned into this awful situation.
"It was just utter panic, just confusion and I was groping for some small answer for what it could be (what had happened to India).
"I was over anxious, I just thought maybe a drink would help, so I went to the hotel."
When asked by junior defence barrister Derek Joliashen why he had told police, "I'm surprised you were so quick," he answered, "My optimism is unbelievable. I'm just one of the world's greatest optimists.
"That allowed me to continually believe India wasn't dead.
"I thought they had then gone to my house and she wasn't there and hoped I would he would say, 'Do you know where India Chipchase is?'
"I hoped she had somehow got out and got home or been rescued or something."
Prosecutor Chris Donnellan QC said Mr Tenniswood had cornered a "paralytic drunk" and "fairly pickled" Ms Chipchase outside a cocktail bar after she had become separated from friends during a night out on January 30.
Chipchase had "downed" six jagerbombs at NBs cocktail bar in Northhampton.
"It was while in this fairly pickled state that the defendant arrived outside (the bar). It had not been too long when he spotted India and went up to her," Donnellan said.
"Others who saw them thought he knew her. He did not. He was overheard to be saying: 'Not to worry, I will get you home safe'. He did not.
"It is very likely his motive was sexual and when she resisted him he was determined to have sex and he grabbed her around the throat and squeezed. He held her until she was unable to resist anymore."
Earlier, the court watched CCTV footage of Ms Chipchase, unsteady on her feet, being approached by Tenniswood. Shortly after, he bundled her into a taxi, giving the driver the address of his home, located about 1.5km from the bar.
"You can see the defendant is speaking very close to her face, quite intrusively," Donnellan told the jury.
"He then took her by the arm, as if taking possession, and doesn't let go from that moment."
Donnellan said Chipchase was raped and killed soon after arriving at Tenniswood's "grim terraced house".
"When she resisted him, because he was determined to have sex, he grabbed her round the throat and squeezed and held her like that until she could resist no more," he said.
"She appears to have put up a struggle, there was blood under the fingernails of her right hand."
Chipchase worked as a barmaid at the Collingtree Pub in Northampton, where flowers and cards were left by co-workers, friends and patrons as a tribute after her death.
According to The Advertiser, she was privately educated at Pitsford School and was awarded a diploma in health and social care at Northampton College.
Her father, Dr Chipchase, has lived in Adelaide for a decade and is known for his work on the management of spontaneous miscarriages.
He is listed as a senior doctor at Lyell McEwin Hospital's obstetrics and gynaecology department and also mentors junior doctors in his field.
The tragedy made front-page news in Britain and Chipchase's boyfriend, Kiwi professional rugby player Evaan Reihana, said he would dedicate his career to her.
The trial continues.
- Additional reporting by Marnie O'Neill
