When someone with custom textures (any) enters a room and plays a match,
the textures display on the next person to play in the position that the person with textures played in.
If the person wins, both people display the textures.
Even after the original person with textures leaves the room,
the textures continue to display on anyone who occupies the position(s) that he did.

Yeah, there's a sticky about that in this very same subforum.

http://forum.toribash.com/showthread.php?t=99603