Did you
1) DO NOT use cups to drink when you’re out with friends. If you must, rinse it with water.
2) Don’t let the waiter open your drink. Open the drink yourself. Poison can be kept in long nails.
3. Finish your drink before you excuse yourself to go pee.
4. Throw remnants and buy a new drink.
Protect yourself. Trust no one. trust your friends that much?