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I checked the Vampire Tropes index and I can safely say we don't have an already existing trope. I can't remember whether or not this was already drafted on Trope Launch Pad, I thought I saw a draft on the pad once, but when I tried searching Trope Launch Pad today I couldn't find it.
Edited by Miss_Desperado If not for this anchor I'd be dancing between the stars. At least I can try to write better vampire stories than Twilight.^ Nope, it hasn't been launched — I found it! Intoxication Through Draining
My previous search searched all the TLP drafts. This time I looked through my watchlist — I really need to clean out my watchlist, I'm watching too many TLP drafts.
If not for this anchor I'd be dancing between the stars. At least I can try to write better vampire stories than Twilight.

Is there a trope where a vampire feeds off of someone who had just taken drugs or gotten drunk and gets stoned or drunk as a result? For example, when Spike talks about his experience at Woodstock on "Buffy, the Vampire Slayer": I fed off of a flower person and spent the next six hours watching my hand move.