If there is a person who I would ever have a conversation with about sex, then I don't see why I wouldn't give them a sex toy. While it's certainly not appropriate to give the gift to someone who you don't know that well or someone you don't have that sort of relationship with, if you do have that sort of relationship then of course you should give the gift. After all, think of how happy you would be to receive a really great vibrator on Christmas morning! I'm sitting on the edge of my seat hoping to get a Hitachi or a new key vibe!
But wait, you say. Surely not everyone is an appropriate person to give such a gift to. How am I to tell which kind of person is an appropriate person to give that sort of gift and which person is better off with socks or a candle?
Of course, there's any easy way to discern whether or not you should give the gift: do you know what kind of toy they would like? If we're talking about your parent of the opposite gender (because nobody seems to have that sort of relationship with opposite gender relationships) or your boss, then you probably have no clue what sort of toy they would want. A g-spot, size queen, ball gag...? It could be anything. That's a sign that you probably shouldn't give the gift. Clearly, you've never had that sort of conversation and don't have that kind of relationship. However, you probably have somewhat of an idea of what kind of toy that your best friend would want because surely you've discussed sexual matters previously. That's a good sign that it is an appropriate person to buy for.
Don't feel scared away from buying anyone a sex toy. This community is filled with fairly open and adventurous people, so it's necessary to keep that in mind. Not everyone is as adventurous or as open as you might be. Some people might be downright horrified if they opened a gift to find a vibrator. Think carefully if you think they'd be comfortable with receiving the gift. If you know what kind of toy they would want, go ahead and buy it. Make it a VERY merry Christmas for them. If you're in doubt, then it's probably a sign that they're not one to buy a toy for.