Here's how I would do it:
In a free terminal:
computer# ssh local_server -L 2222:127.0.0.1:2222
local_server# ssh remote_server -L 2222:127.0.0.1:22
Then, if you want to connect to the remote server directly, you can just connect to port 2222 on localhost.
For instance, if you want to proxy through the remote server: ssh -D 8080 -fCqN -p 2222 localhost