Someone gives you news that may be absolutely right; perfectly true, but is not good news. (thus should not be celebrated with the standard "right on")

It still means fuck off, but it’s a fuck off on steroids with its fists clenched, eyes staring and a snarl on its lips. But that’s not the end of it, you can be told to “ most definitely fuck right off”, where in addition to staring and snarling with its fists clenched sweating and trembling with anticipation for the tiny trigger that will let it rip your head off and shit down your neck. There are numerous other variations until you are told to “most fucking definitely fucking well fuck right fucking off”. If this sound incoherent it’s because it is; you are now faced with a berserk, ninja vampire with titanium talons and diamond teeth who is a hairsbreadth away from howling chaos and the total destruction of you, your family and all your ancestors so that you become not even a memory.

at once, immediately
from the beginning

Similar to right off the bat, right off the smack refers to the first thing that is necessary, done, or noticed. The modification of this phrase is used to ground the jargon to just getting off the effect of heroin, smack, which impairs cognitive function.

Immedietly or straight away

Do/did something right away

To have an extraordinarily good time, most commonly involving the consumption of alcohol (after you've had a pint)