If the child does like the stinky smell, don’t panic. It isn’t that unusual for autistic children and doesn’t mean they’re doomed to be stinky forever. I think that a familiar body odor can be comforting, especially if it “drowns out” other unfamiliar or unpleasant odors. (Noises work this way, too.) Most people’s households are full of scents, which can be distressing to sensitive noses. Try rotating when you wash things. You and I may love getting into a fresh, clean bed after bathing, but this may be too much for your child. Do not wash your child, their bedding, and cuddly toy all at once. Keep one blanket or cuddle toy “stinky” longer so that your child still has that comforting presence.
Try using unscented laundry soaps, fabric softeners, and drier sheets. An autistic kid can be overwhelmed by artificial fragrances or even allergic to them, especially if the child has asthma. Also, wash things when the child is away at school so she does not see them removed from the bed and remake bed before the child returns. Also, have duplicate sets of favorite sheets and blankets so clean sets are always on hand for a quick change of bed linens when they are not watching.
It may not be that the child likes the stink, though. It’s more likely that they are overwhelmed by the scent of your cleaning supplies. Use unscented products for all your cleaning and this should make the problem easier to manage.
Autistic children also tend to like familiarity, so if you use a lot of different cleaning products with a lot of different smells, you are making an already difficult situation much worse.
There may actually be some scents child likes. They probably won’t be perfumey ones, but perhaps likes vanilla or lavender or lemon. If so, try to add that particular scent to freshly laundered items.
Do you have identical ones for use while the others are being washed? It might help. Also, perhaps she could help pick a detergent she likes the odor of?
A child who is hypersensitive to smells is overwhelmed by the onslaught of odors and scents from all directions. Other children and teachers often do not notice the scents that are bothering someone who is sensitive to smells. One of the most common complaints is from a child who can’t concentrate on their school work because all they can focus on is the smell of cleaning solution used to disinfect the school. Another issue sensory children may face is the smell of wet clothes in the winter time when children come in from the playground.