If stained "fishy" smelling and squatting to urinate frequently, then I would wonder about an urinary infection and/or bladder stone problems. If there is a non-smelly reddish tinge then it is probably ordinary staining.
It is possible that yeast or mite activity is adding to the problem.
For reddish stains on feet, on the 'stop' between the eyes, in the petticoats, in folds under eyes or stained chest hair ( the last two both Japanese chin problems ) a very little Thornit powder carefully placed will often sort out the problem.
Cavaliers......Faith, The Ginger Tank and Woody.
Japanese Chins.... Dandy, Benny, Bridgette and Hana.
Remembered with love......... Tommy Tuppence and Fonzi