How to silently trade with siblings

Step 1 - Grab a piece of chocolate
Step 2 - Your sibling get out of their room, attracted by the noise
Step 3 - Hand them the chocolate piece to buy their silence
Step 4 - Wait 'til they break the chocolate piece in two and give you one half
Step 5 - Part ways and pretend nothing happened

Congratulations, you successfully made contact with your sibling without saying any words they could use against you

The company is not responsible for siblings not sharing the chocolate piece