Pistorius is on trial for allegedly murdering Steenkamp on Valentine’s Day last year.
He has pleaded not-guilty, claiming he had accidentally shot her thinking she was a burglar and that her death had been a tragic accident.
Taylor testified that she and Pistorius met at a rugby game in 2010 and started talking over social media when he added her to his Facebook page. They started dating when she was 17 years old and she thereafter spent about four days per week at his home.
According to Taylor, Pistorius used to carry his firearm everywhere with them and would keep it on the bedside table or next to his artificial legs on the floor on his side of the bed at night.
She could not recall Pistorius ever “ventilating” his legs at night by putting a fan on them or putting them outside.
She testified that she had on more than one occasion heard Pistorius screaming in anger at her and other friends, but he definitely sounded like a man and not like a woman. She admitted in cross-examination that she had never heard him screaming when he believed his life was in danger.
She testified about an incident on a night after she, Pistorius and some of their friends had visited the Vaal Dam.
They were traveling back from the dam with Pistorius’ friend Darren Fresco when they were stopped by the police because they were speeding.
She said Pistorius and Fresco, who was driving, climbed out but Pistorius left his gun on the car seat.
When the policeman saw the gun, he told Pistorius he could not lave his gun on the seat like that, took the firearm and disassembled it.
“He shouted at the policeman because he said he was not allowed to touch his gun.
“Oscar got very angry and eventually they gathered the bullets and put the gun back together. After we left Oscar and Darren were pretty anxious and a little irritated with the policeman and so they laughed and said they wanted to shoot a robot and then Oscar shot a bullet out of the sunroof.
“There was a very, very loud sound. They both laughed,” she said.
Afterwards they drove to a house where Pistorius signed some papers for a firearm before they went to Sandton for a meal.
Taylor testified that she and Pistorius had broken up for the first time when he took a woman called Anastasia for dinner while he was overseas.
They broke up the second time when he took Reeva Steenkamp to the Sports Awards in November 2012.
At that stage they already had problems in their relationship, but they were according to Taylor still together as a couple.
Taylor twice burst into tears when she testified about her break-up with Pistorius. She however admitted that she had accompanied another man to Dubai while Pistorius was in London for the Olympic Games.
Taylor insisted they had broken up and were not seeing each other at that time.