a leeching group is a telegram group in which there are bots which download the torrents you give them links to (usually to gdrive or other cloud storage) these download the torrents faster (since they run on servers) but as the name suggests, do not seed the torrents. and all the torrents you make the bot download are available publicly for everyone in the group. leeching groups were very popular during lockdown, I haven't checked them out for a while though.

the github I linked is such a bot, it can be self hosted and used for downloading torrents (i.e. making your own leeching group)