Don’t sweat it, I do this all the time in my wife’s X3 on the way to taking my kid to school. Never in my 15yrs of dropping her off, have I ever spilled my coffee. Granted, it’s within a 7mi. uneventful drive but I am the same as you, I don’t like drinking hot coffee from a sipper mug.I actually use quite a few of those. And agree no spill ever. Cant beat their prices at Costco.. especially when you can get 2 for $20.
That said sometimes I want to drink my drink (hot or cold) faster than taking small sips. Which is exactly why I don't always use a cover.