I don't taunt, typically, out of respect for my opponent. Usually, I remain motionless, unless I'm finishing a buffered combo, or I'm facing backward (in which case I will turn to face them). Sometimes if I'm in a stance, I will it as well (ongyoin). I will only taunt after I win a match under three conditions:
1) My opponent thought he could win by really just spamming the same retard attack over and over again. 'Cause fuck those guys.
2) If I lost a match against them previously and they taunt me upon match end. If they just want to spew shit, I have no problem scooping it back up and spoon-feeding it to them.
3) My opponent was of near equal skill, and I use the "taunt" out of respect. This only applies to characters who have less offensive taunt, such as bows, etc.