The 92-year-old is smiling in her bright blue monster onesie, but still carries a cane from a fall she had in April.
Thomason was getting ready for a Polynesian-themed dinner at her retirement village, Summerset at Aotea, Wellington, when she fell, breaking her pelvis.
(Wellington Free has its major fundraising appeal, Onesie Day on September 8.)
"I just turned around too quickly and once I started to go I couldn't stop."
She managed to get into a chair, which is where fellow resident and friend, Nonie O'Neil, found her a short time later.
Wellington Free Ambulance (WFA) was there in a hurry, and bundled Thomason off to Wellington Hospital.
The laughing gas made her blissfully light-headed on the journey to hospital, but she faced a long wait for a bed. WFA staff stayed with her and helped her pass the time.
She spent six weeks recovering at Kenepuru Hospital in Porirua and still can't turn over in bed.
But she had nothing but praise for the ambulance staff – and the team at Kenepuru – for the care and attention they gave her.
She will be among more than a dozen residents, and hundreds of Wellingtonians who will don a onesie on September 8 in aid of the free service.
WFA was aiming to beat last year's total of $160,000 for Onesie Day this year, the charity's largest annual appeal.
"We currently have 90 businesses on board and 101 schools taking part as well as the annual street appeal," WFA spokeswoman Sarah Coulthard said.
Aotea at Summerset will host its annual fundraising lunch. It's raised almost $15,000 for WFA.
"They're here an awful lot and they take such good care of us. Sometimes they're here twice a day," O'Neil said.
Maurice Paulsen, 91, chimed in from under the hood of his dinosaur onesie: "We've got to do something for the free ambulance. It won't be long till we need it ourselves".