Ms Mansell 28, said the last stage of labour was intense and she vaguely recalled chewing on her partner's face towards the end of it.
"I didn't realise I was doing it until he said 'ouch' and I had to find something else to bite on."
The dad was sleeping off his ordeal while his partner carried on her Computers in Homes class with Leslee in attendance.
"She seems like a very relaxed little baby," said Tawhero principal Chris Dibben "she must take after her mum".
Leslee is Ms Mansell's third baby - her daughter Sussy is a student at Wanganui Intermediate and her partner also has three children.
"We now have six between us and that is enough - I'm delighted with this wee girl but I want [to] get ahead with my studies and I think it's great for my children to see me learning new skills."
Ms Mansell said the children were delighted to wake to the sound of a new baby, and her fellow students were pleased and surprised to welcome Leslee to class.
Computers in Homes is at-school study for families. On completion and getting qualifications, students are given a recycled home PC.