My flatmate and me are very good friends. Both me and her put a lot of emphasis on cleanliness in our whole apartment (what is suiting completely fine).
For a few days her family stays here for a visit and her brother (beginning of his 20's) is using our toilet as well. However, the brother regularly flips up the toilet seat when peeing (in standing position) and also doesn't clean the toilet very well after defecating. Due to the fact that we have separate male and female toilets my flatmate doesn't know about the sanitary legacies of her brother.
- How can I politely explain that I wish to leave the toilet in a clean condition?
- Should I tell this to her brother directly (without involving any third party what could make her feel ashamed)?
Circumstances: Western Europe