To make a movement with your head kind of bobbing down? In the sign of disagreement/agreement
When you join to independent clauses with a conjunction you stablishes the equality in this clauses, however in this case you can see that the clauses have a causal relation, it could be said If you don’t hold my hand, I will drown, in this case the best conjunction to put the clauses together is “or” “Hold my hand or I will drown.”
There needs to be a question mark after the first sentence.
