I won't do them at the table, but it helps me get a good visual in my head, and being able to name specific poses helps in the creation of aspects. Plus I just like the idea of using authentic ones.
How concerned are you with authenticity? Are you looking for a strong visual, or do you want the proper name attached to the technique? Or would someone suggesting youtube videos be more what you need?
I ask because Taiji doesn't really use five element theory. There are ideological correlations that have formed over time, but they're superfluous to the actual practice.
If you want, I can explain the Shísān shì (the core thirteen 'postures' of taiji) and point out which correlates with what trigram/element (
this is a useful overview, but lacks the trigram/elemental correlations) and how they're used to generate the 26 or so postures you commonly see in forms, but that's going to be a long, boring post without knowing exactly what you're looking for. Lavecki121 linked to a breakdown of the
Beijing 24 form (
this is a complete run-through of the form).
You may also want to look into the
Jiǔzì yìn. It isn't taiji, but it is a Daoist practice that uses mudra, and that article has the hand positions as well as the corresponding mantra. However, mudra/mantra are outside my field of expertise, so that's all I'll say about them.