How do I trigger a loose tooth? (Growing together)

Thank you for your suggestions! On an another forum I got an advice to spam toothbrushing, unfortunately that didn't help. But I found a solution at last: my sim got into a fight and lost a tooth this way. That unlocked the tooth milestone!

EDIT: In case you're wondering, yes, he was able to put the tooth under the pillow and yes, he got his certificate!

Yeah, another way is to find a way to... well... get hit. That could include stumbling while riding a bike or falling while skating.

Idk I had this with child sim twice already and I only played that child sim this week
maybe not brushing teeth and eating snacky snacky things? or then its just random chance I guess

Actually, one of my Sim children got a loose tooth after brushing her teeth.