Ball hits batter on a bunt attempt
 

Batter squares and extends his arms to lay down a sacrifice bunt. The pitcher throws an inside pitch. The batter brings his arms in toward his chest, bringing the bat straight back. The ball hits batter in the chest. I called a dead ball, asked my partner if he offered (no) and sent the runner to first base. Did we get this right?

yes you got it right

Presuming the ball wasn't in the strike zone.

You asked for a "check swing" appeal. Partner said he didn't offer. You got it right.

Different story had he offered.

If he offered at the ball, and in my opinion offering doesn't mean NOT pulling the bat back. He must make an attempt to bunt to ball, aka moves the bat towards the ball. Then it is a dead ball strike.