The topic of Coke Blak came up at lunch today and since we don’t have it around here, as near as we can tell, we made our own. The recipe:
1. Get a sixteen ounce cold cup
2. Fill with ice
3. Add ~10 oz Pepsi (unfortunately that’s all we have around here)
4. Add two shots espresso
5. Add one or two shot(s) half-and half (half-and-half makes everything better)
6. Stir.
7. Share and Enjoy.
The soda really brings out the bean flavor, which is nice. I believe further experimentation is required to find optimal ratios and soda choices, but it was a solid start.
UPDATE: Hummingbird on crack would be the physiological effect.
Not So Fast 
If you pour the shots and the half-and-half first, there should be no need to stir, the carbonation will mix the liquids perfectly well.
Or, at least, that’s how it works with liquor. Stirring doesn’t do anything but make the drink go flat faster.
ymmv, of course.
Interesting. Clearly more experimentation is needed. I’ll try again tomorrow.
In the name of science, of course, right?
In the name of truth, science, and being hopped up on legal stimulants.