Cup Kiss
When you drink from someone else's cup, especially when using the same spot as the former user.
Cup kiss: two examples
Person A: Hey that's my cup!
Person B: That's ok, you're not ill, are you?
Person A: Hey that's my cup!
Person B: Eww, really?
Person A: Hey that's my cup!
Person B: That's ok, you're not ill, are you?
Person A: Hey that's my cup!
Person B: Eww, really?