I made a needlework piece that had pieces of cake, cookies, ice cream sundaes etc and the words 'What happens at grandma's stays at grandma's' and gave it to mum. She worked it out from that.

She then called my sister out and showed it to her. Her response 'oh, that's nice'. Then 10 seconds later, jumping up and down and screaming when she worked out what it meant. That was the best reaction we got!

PIL were told face to face, most friends were via email or phone.