When drinking something causes a vivid flashback to something you drank before, whose taste suddenly resumes in your mouth, usually in a negative way (something you got too drunk from, something that caused a bad hangover, etc.).
Tends to be instantaneous and fleeting like any other type of flashback.
Referential to/influenced by the acid flashback term, "retrotrip".
I'm avoiding things that remind me of alabama slammers this week (anything punch-red, anything with 4+ ingredients, etc.) because I don't want to RETROSIP. You know, like RETROTRIP?