The Lock Cup
The "Lock Cup" is designed for people who share facilities at their work place, such as the kitchen.
The cup has a hole which prevents most people from using it. Only the owner of the cup can use his shaped key to close the hole, pour the coffee and enjoy the drinking.
If you don't trust the people, why would you keep something that you drink out of anywhere near them? And especially after they are pissed off that you hate them so much that you have installed security features on your mug. Disposable styrofoam might be the way to go.
