OK, but what if you cover the hot coffee mug with the creamer carton? Then it’d insulate the coffee AND warm the creamer instead of the room, right, for an even hotter final mix…?
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Why not just nuke the mug with coffee and cream already in it? That’s what I do. I suppose purists will say that it changes the taste of the coffee, but with sugar and cream in there, I don’t think it’s going to make much difference.
And we love to add our own self important anecdotes. So I’ve been using plant based creamers in my coffee. Waiting on the French press, First I splash hot water from the kettle into my cup. After I plunge the press. I empty my cup and immediately add the lightener then the hot coffee. I don’t even need to stir. 
Yeah I don’t stir either. Homogenised coffee is for people who don’t like surprises
This, I believe. And I spent the last few years of my career working on heat transfer.
Unhomogenized coffee is for people not lazy enough to put the creamer in first. Let the coffee do its own stirring. Work smarter, not harder. 
I have to ask: how slow do you drink your coffee?
I don’t gulp it down all at once.
Like the apocryphal Groucho Marx remark on You Bet Your Life, I take the mug out of my mouth every once in awhile.