I kind of like to taunt at the start of the match if the guy doesn't immediately start coming towards me. It's kind of my sign of saying "Have fun, and don't take it too seriously." I also like to do it when both of us are keeping our distance in the middle of a fight, to try to get them to come in closer. Granted it has to be a short taunt.
I'm actually pretty self concious around people I don't know when I fight. Over the years, I've gotten into a habit of taunting my friends any chance I can get, but against a random person I'm usually a little timid to taunt after taking a stock, even though it feels alkward just standing around that one or two seconds waiting for them to respawn... Though I've gotten into the habit of flipping around with Villager's nair while I wait for them to respwan instead...
But on the other hand, what is teabagging, exactly? I've seen that word being thrown around a bit, and I'm not quite sure what it means... I mean, I know what it is in FPS games, but Smash Bros?