Found this out last night in Totgc 25h.
If you're a mage and you happen to have a Snobold Vassal jump on your back, simply use invisibility. What this does, when you come out of invisibility, is that the Snobold will no longer interrupt your casts. This allows you to dps as if it were never on your back to begin with.
Granted it can still interrupt nearby players' casts, so you should be comfortably away from other people. However, if you're in a dps crunch while getting the first boss down before the second comes out, this is a good way to keep ranged off your mob as it poses no other immediate threat.