It's something to do with the taste and that sort of energetic buzz you get going on in your throat. Drinking cold water just sort of... synergises, very temporarily.
I'm not sure if fizzy coke synergises more permanently, but people do reccomend it with gabapentin... but that's just a nightmare for metabolism, god knows what's going on beyong the inhibator or whatever, or how that interacts, other than with fat, etc . May be the same for pregabalin, not sure. I do feel like fat brings it out after an hour or two, but I couldn't say for certain. I'm more experienced with gabapentin really, though they do feel identical to me, other than onset.