Grog is an old British Navy term for a drink of watered down rum and has been extrapolated to mean any strong drink. However I can see where the confusion lies. Julesnus is supposed to taste like the Swedish Christmas drink called "Glögg" - and glögg is very similar to mulled wine, red wine heated up with whole spices and citrus peels, sometimes fortified with extra brandy or aquavit.
I did have some correspondance with the guy in charge of the recipes at Gotlandssnus, the people who make Jakobsson's and the original Julesnus. While he didn't give any secret recipes away, he said that the key to his success with flavours was to produce the snus from the tobacco and then add just the right blend of very high quality natural flavouring extracts. However if trying to make it at home I would probably not use extracts or oils as they're very hard to get the right dose for a small batch.
To replicate the flavour at home might require a bit of experimentation. My suggestion would be to try and produce a fairly light tasting snus from tobaccos that are not too dark and rich, replace some of the water in the recipe with red wine, then add ground spices AFTER THE COOK (my experience of adding aromatic ground spices is that the aroma tends to evaporate off if added before cooking)
The traditional spices in Glögg are: Cinnamon, cardamom, clove, ginger and orange peel. I would personally take the cooked snus after it has cooled down, add the finely ground spices carefully a little at a time and mix in well before tasting. Taste it bearing in mind that the snus has not aged at all. From smelling my can of Julesnus, I reckon the main spices are cinnamon, cardamom and clove (in that order) ... a few weeks of ageing will help the spices go right through the blend.