Spawn Rate Glitch

I saw a thread talking about a glitch where you keep joining in and out of a private room. By doing that they made the monster spawn nearly instantly. When I asked how it was done some days later the thread was closed and my posts deleted. So does anyone know how to do it? If so please post on this thread.
Thanks in Advance!

You just type /join (room name)-999999
Once you kill the mob or mobs you need to then you just re-enter it.

not sure how this is a spawn rate glitch

but to keep on joining random rooms, do /join name of room followed by 6 or more 9's
e.x /join battleon-9999999