It implies an intense desire, often in a way that lacks self-control or dignity. She was slobbering over the idea of owning the luxury car.
Pro Tip 2/3
Potentially Negative
Can be seen as negative, indicating someone is too eager or desperate. He slobbered over the job offer like he had never seen money before.
Pro Tip 3/3
Casual Expression
Best used in informal situations among friends, not in formal or professional contexts. After the trailer, movie fans were slobbering over the release date.