If I understood well, you want to bind "cheer" on more than 1 key ?
Just repeat the command for the 2 keys.
It would be :
bind v "vsay cheer Yeah !"
bind g "vsay cheer Yeah !"
bind c "vsay cheer Yeah !"
If you want, you can create a toggle bind which would change the place of the key.
Here's an exemple. The toggle key will be F12.
Default your cheer bind is on the V key. If you press F12, it will delete the V bind and put it on G. If you press the toggle again it will remove C and bind G.
I can make the script if you want, just let me know