If you are an anxious lover and you have started thinking about what to get your 'significant other' this Christmas then you won't go far wrong with a pair of special stockings. These special stockings can be whatever suits you best; fishnet, sheer, patterned, silky thigh highs or whatever you choose. But I do strongly recommend you check out her proper size.
How to do this without her knowing? Good question and you may need to use some "Dick Tracey" (pun intended) tactics here. It's amazing really how women know when someone has been into their lingerie drawer so you will have to be very discreet. Before you touch anything in her drawer after opening it, take a good look at how everything is set out. Most women know to within an inch where a certain pair of stockings lives and if you don't put them back exactly right you will get a question or comment about "someone's been into my drawer!" and we don't want that, now do we?
Just be sure to put everything back exactly as you found it after checking what sizes and brands are on the spare stocking package labels. Most stockings don't have sizes on the stockings themselves so you will need to read the new packages. If there are no new packages of stockings in there then you will need to invent an excuse to get her downtown and into a mall without raising her suspicions.
Once you are in the shopping centre or mall together, see if you can entice her into a lingerie shop or super department store and past the lingerie section. I'm sure while you are in there and looking around, see if you can discretely get her sizing from her while you pretend (or honestly) admire something and say that you think that would look nice on her. Women love these types of comments!
That way you may also get her dress sizing and this will be a big help to most shop assistants working in a lingerie shop because they will then know what her stocking size is most likely to be with a 96% accuracy. Depending on the style of stocking you end up buying this close a fit will be pretty well comfortable for her to wear.
Now that we have the stocking sizeing sorted out why stick at buying only one pair? Why not buy her a pair for a few occasions and when she wears them she will be able to remember when she wore certain others. Memories are precious and better when shared.