You can look for personalized heat-sensitive coffee mugs and print your favorite cheeky catchphrase/ image for him printed on that. He may only see a black boring mug but the moment he pours a hot beverage in... bang you hit him with your evil (and loving at the same time!) message.

Something like this: https://www.amazon.com/Custom-Magic-Mugs-Sensitive-Personalized/dp/B01ETZLR44

Hope this helps!