Jasper will do this if he gets onto the top floor of my house - solution - he's not allowed up there - full stop.
If your dog has taken to weeing on the bedding - for whatever reason - you need to stop her going up there all together - imho.
Sorry - that's not meant to be harsh - and I am very sympathetic. The only time my boy can get upstairs to the top floor is when I least need it - ie usually visitors are coming and will occupy the two rooms up there - so I just can't afford to have any accidents on the bedding,
Plus I think it sets the scene for potential problems on other bedding - so he's not allowed on the beds.
(Although he did sneak on mine the other day while I was wrapping pressies and I didn't see him - but bless he'd curled up and gone to sleep on my dressing gown - aaaaaaaaaaaah.
)
If a bitch is doing it in her bed too though - has another dog been around at all?