I used to love sniffing bags of Heroin after a night spent tripping on LSD. Its about the most euphoric warm blanket you could ever find in such a situation. If you take it from the start it definitely dampens it significantly.
Id also like doing these 3-MMC/heroin injections. That felt amazing but im sure was a terribly unhealthy combination to use intravenously. Probably spent a easy month doing it daily at one point.
Sometimes i would mix 15mgs of 4-ho-MET in the shots as well. Just seconds after i pushed the plunger down and injected the solution the white celing swirled into a kaleidoscope. Literally every colour of the spectrum enveloped me and the rushing euphoria from the 100mgs of 3-MMC was mindblowing. And a few minutes later I'm greeted with the warm embrace of my close friend, heroin "two quality bags"
Liked to use bk-MDMA or Mephedrone back in the day with dope also. I prefer mixing with empathogens over cocaine. Causes me less anxiety and a smoother come-down. It's pretty hedonistic, the euphoria is intense.