The BitTorrent protocol basically works like this when you download a torrent:
- a tracker has a list of clients that have some data of a torrent
- you want to download that torrent, so you ask the tracker for this list
- after you receive this list, you ask the clients on this list to upload their data to you
- repeat 3. until you have the whole torrent
As soon as you have something downloaded, you become a client on the list of the tracker that theoretically has the torrent available for others. So you would become the "client being asked" of step 3 as well.
But how can you be asked? In a P2P networking context, you can only "be asked" if you have a port open that allows connections to it. Otherwise it's as if you gave people your home adress but your mailbox has a hole on the bottom that leads directly to the garbage can beneath it, so all mail is immediately lost. Completely unusable.
In other words, it's (basically) impossible for you to send the torrent data to someone else. You're a leecher, someone that doesn't give back to others. If everyone would act like you, torrents wouldn't work at all.