Sharing air with an octopus or another alternate air source is the safest and preferred solution for an out-of-air emergency. To share air using an octopus:

1. Your buddy signals that he/she is out of air, and needs air.
2. Immediately locate your octopus and hand it to your buddy.
3. Your buddy accepts the octopus, removes his/her 2nd stage, and replaces it with your octopus.
4. Hold your buddy's right BCD strap with your right hand. Your buddy does the same. This leaves your left hand free to vent air from your BCD during ascent.
5. When you and your buddy are ready to ascend, display the ascend signal and begin the ascent. Continue holding onto each other, and remember to maintain neutral buoyancy by periodically venting air from your BCD. Perform a safety stop if your air supply permits.