Aren't kids hilarious?

My DS started this not so long ago as well and it seems to be losing it's novelty.

For us, we would move his hand and say "yuck Cooper!" and he'd stare and slowly move the hand away.

Then for a bit he thought it was a game and would look at me, slowly put the finger up to his nose and smile.......so I thought I'd try something different.

When I saw him going for the nose, I'd say "hey Coops" and when I got his attention I'd put my finger on my jaw (like I'm thinking) and say "hmmmm" then point up and say "I know, let's go play" and take away his attention to something else.

This worked well and now when he wants to say something, he puts his finger to his jaw and mimics that same "hmmmm......I know!" - so sweet..

So diversion may work at 21 months - my DS was around the same age as yours so I think diversion works better than explanations IYKWIM?