I once snorted 2mg of Suboxone 2 hours after a hit of heroin, soon after i was in precipitated withdrawal, it was mainly the feeling like i was going to die, panic sets in, coughing up loads of fluids, then i get cold akin flu, its like day 3 in withdrawal, but hits you harder faster.
Was always told to wait 24 hours going from heroin to buprenorphine, but i'm fine after waiting 12 hours