Depends on the oats...
The milled kind, like Mornflake, are usually best direct in the bowl, dump in hot water fresh from the kettle, stir a bit, leave to soak for a couple of minutes, top off with more water and then leave until cooled to eating temperature, with occasional stirs.
The rolled kind like Quaker, Scots, etc, are best with milk - Melt some butter in the pan, dump in oats and quickly stir in, then add milk and keep stirring until as desired (gloopy, runny or more solid). Both I prefer with some sugar, as not found the right amount of salt yet.
Other additions and embelishments usually too sweet, but plenty of options to suit different tastes...
Any suggestions how to spice it up a bit?
'Porridge' is simply a dish made with any number of wheats or grain type stuff. Polenta, rice, corn, mielepap, barley, loads of options. Just about every nation in the world has several variants on it, with numerous ways to spice their own up, depending on whether you like salty, sweet, savoury or whatever.
Have a Google, as there are thousands of recipes -
https://en.wikipedia.org/wiki/Porridge
I'm on a cost cutting exercise... and decided on porridge for dinner
At Christmas time, too?
OK, for an authentic, traditional recipe that matches this festive season, use half, a third or even a quarter of the oat quantity in recipes, and water it down.
That makes it gruel, and is dinner fit for Scrooge!!