Long hair cats and dogs have a hatrder time cleaning themselves so you're going to have to helpher a bit by cleansing the area. They make pet wipes for cleaning them but you may have to use something a bit more wet with pet shampoo on it. You don't have to dunk her though if you do it at the edge of the sink. Make sure you reward her with treats so she comes to see it as a positive experience, not a negative. Have they checked her for a urinart tract infection? That can cause dribbling and if she can't clean herself well, the hair will retain the smell after drying. I have a long hair cat but I've never had to shave him back there as he's fastidious in his cleaning. Is she elderly? It's amazing how they can fight human care, they also make "cat bags" to put cats in while you're working on them. But they HATE them and if you have to do this consistently I wouldn't recommend it. They have memories like elephants and I have the scars to prove it!(Not really) I used to work with a vet at an animal shelter and it was soooo nice to do that sort of thing while they were knocked out for a spay or neuter--much easier!!