Am I doing this right? Toddler hitting sibling

This is an example that would guarantee my 16mth (A) to hit their nearly 3yo sibling (G).

I would be cuddling A on the floor, and G comes up for a cuddle too. One child on each leg. When G starts cuddling me A starts to voice upset/angry noises, then starts whacking G on the back.

I put A on the floor next to me while saying No. I tell A that we do not hit, and that hitting hurts and makes people sore and sad. I tell A they need to say sorry.

A doesn't have words yet. But A is understanding things, like tell me in sign Finished or More or Water. I just want the message to be consistent as they get older.