First make two coil-like rings. Never mind inductances. Just coil some thick copper wire so that your fingers go nicely inside. Connect a keying cable to these rings.
You also need a small audio oscillator. A simple circuit using 555 timer IC is fine.
Put the oscillator in your sleeve.
The coiled rings go to your fingers like this.
Attach a piece of aluminium tape here.
CW sounds are heard when you touch the al-tape in another operators hand with both rings, and vice versa.
See & hear this video clip:
