IN YOUR CLIENT..

on *:INPUT:*: {
  if ((!mybot == $1) && ($nick == [BB]Funkd0c)) {
    msg Funkbot !assign $chan
    halt
  }
}

IN YOUR BOT'S CLIENT..

on *:TEXT:!assign*:?: {
  if ($nick == [BB]Funkd0c) {
    join $2
  }
}