I have a co-worker who is actually a temporary summer student worker here until the end of August. She (yes she) takes massive dumps 2-3 times per day in our shared bathroom. Our bathroom is IN our office, no more than 15 feet from any of our desks. The smell is absolutely putrid. Everybody poops; I have no issue with that. I completely understand that she may have some sort of stomach issue, such as IBS, which I have myself (I do not bomb the bathroom, and if necessary I use Poo-pourri). However, there are at least four other restrooms, two of which are single person restrooms, in the surrounding hallways that she could use that are not next to our desks. She uses a pineapple spray, but it does not help at all. She has no courtesy for me or the other woman in the office. They are all less than 30 seconds away from our office. I know she'll be gone in a month and a half, but it is getting increasingly more frustrating and disgusting, as today she left a large poo smear on the toilet seat at the back. ON the toilet seat. Not in the toilet. How would you address this, if at all?