The mother of a toddler who died after allegedly being tied face-down to a "cage" bed asked her boyfriend: "Why would you do it?", a court has heard.
Lauren Coyle, 19, told Liverpool Crown Court her daughter Ellie-May Minshull Coyle was lying on her back and was not restrained when she put her back into bed after she woke at about 7am on March 23 last year.
A post-mortem examination found that 19-month-old Ellie-May died due to "forcible restraint by ligatures in a face-down position complicated by hyperthermia".
Coyle said she had fallen asleep on the sofa after putting Ellie-May back to bed and had woken when her father, Sean Coyle, visited the flat in Preston, Lancashire, at about 9.25am.
Mr Coyle went into Ellie-May's bedroom with Coyle's partner Reece Hitchcott, 20, but rang emergency services when he realised his granddaughter was not breathing.
Coyle told the court when Hitchcott took Ellie-May out of the bed she noticed what appeared to be a black Velcro strap around the toddler's ankles.
She said: "I said to Reece: 'Did you do this? Why would you do it?' And he said: 'I'm sorry.'"
Ellie-May was allegedly bound by her legs and chest and forced to sleep face-down in the bed - a purple Frozen bed, based on the Disney children's film - which has been described in court as being made into a "monstrous cage" with cot sides placed around it and covered with blankets and towels.
It is alleged Coyle, Hitchcott and their lodger Connor Kirby, 20, living with the child in the two-bedroom flat at Ward Street in Lostock Hall, all knew what was going on.
Coyle told the court the bed had been converted by Hitchcott.
She said: "I did tell him that I didn't like it but I never told him to take it down.
"I asked Reece what it was for and he said 'give it a couple of weeks and Ellie will be in a routine and settling', so I just took his advice."
Giving evidence on Tuesday, she said: "I should have stood my ground and got Reece to take the bed down."
She said Hitchcott would put Ellie-May to bed but she would go to her if she woke in the night and never had difficulty getting her in and out of bed.
Coyle told the court Ellie-May, who she had with ex-boyfriend John Minshull, was her "world".
But she said the toddler would have tantrums and bang her head off the floor and doors when she did not get her own way.
She said a text message she sent to Hitchcott saying: "I've smacked her loads" referred to her smacking her on the back of the hand once or twice following those tantrums.
The court heard in one text message sent to her partner on March 8, she said: "I literally just feel like jumping in front of a train.
"I just feel down with this child constantly being naughty and I'm so stressed out it makes me feel dizzy."
In another message, sent on March 17, less than a week before Ellie-May's death, she wrote: "That child's f***ing woke me up screaming the whole flat down banging her head. Feel so knackered."
Coyle, of Collins Road, Bamber Bridge, Preston, Hitchcott, of The Fieldings, Fulwood, Preston, and Kirby, of Octavia Court, Huyton, Liverpool, have all pleaded not guilty to manslaughter.
They also each deny a count of causing or allowing the death of the child, one count of child cruelty by "caging" the child in her bed, and another count of child cruelty by restraining her in the bed.
The trial continues.