Non alcoholic- my favorite afternoon drink is to warm up apple juice and put in the flask with some powdered ginger.
Coffee in the morning though. :coffee2:
If I've got a long session on the plot, I take a flask of tea and a flask of soup - got a nice dumpy thermos like this one: https://www.johnlewis.com/thermos-king-food-flask-stainless-steel-470ml/red-silver/p3777605?sku=238225394&s_ppc=2dx92700064091866168&tmad=c&tmcampid=2&gclid=CjwKCAiA4veMBhAMEiwAU4XRr06myfHzZ2za-7OljinhywUR1QpT7iCHxeIvR38a131ict4Jq7ntDBoCaGoQAvD_BwE&gclsrc=aw.ds - don't often use the spoon as it's as easy to drink a smooth soup out of the cup.
ETA - blimey, that's a long link!