The body of India Chipchase, 20, was found on a mattress beneath a sheet at Edward Tenniswood's home in Stanley Road, Northampton, on 31 January.
Mr Tenniswood, 52, denies the charges.
He told Birmingham Crown Court they had twice had sex and Miss Chipchase said she had not felt that happy "in ages".
Demonstrating to jurors by placing his own hands around his neck in a rubbing motion, he said: "She puts her hands on top of my hands and moves my hands down to her neck."
He added: "It's a very organic thing."
Mr Tenniswood said that she then moved his hands away.
He earlier described how he hugged his victim "liked we were posing for a selfie" after claiming she kissed him first.
He claimed the moment was "an incredibly moving thing" as he described he and Ms Chipchase embracing and looking at their reflections together in an upstairs mirror.
"She just made this incredibly moving comment which at the time was very sweet," he added.
"It was a very 'India' thing to do."
He described how the 20-year-old had injured herself and scratched him after "falling backwards" to the floor while trying to sit on his downstairs sofa.
Immediately afterwards they shared a joke about the incident and she gave him a French kiss, he said.
He also claimed he gave her the "grand tour" of his rented terraced house, which on Tuesday he had described as "squalid", and led her to an upstairs bedroom with two plastic cups of wine.
The pair sat on a bench in the bedroom, he said, and were "fixated" on the mirror opposite them.
"She said: 'Oh, it looks like we're in the middle of an oil painting and she put her arm around me and squeezed, like we were posing for a selfie.
Mr Tenniswood continued: "I looked at her and said 'India' and gently kissed her.
"She reciprocated, and it developed into a proper kiss."
Opening the trial last week, prosecutor Christopher Donnellan QC said Mr Tenniswood turned up outside a cocktail bar on 30 January, where Miss Chipchase was in a "fairly pickled state".
"He was overheard by others to say, "not to worry", and he'd get her home safe - he didn't."
The trial continues.
A man accused of raping and murdering a barmaid has claimed she placed his hands on her neck during "loving" sex at his house.