What are we to take from the fact that the Queen takes a sip after her toast but not taking one after POTUS?
this from wiki…Putting one's glass down before the toast is complete, or simply holding one's glass without drinking is widely regarded as impolite, suggesting that one does not share the benevolent sentiments expressed in the toast, nor the unity and fellowship implicit in toasting itself.[16] Even the non-drinker is counseled not to refuse to allow wine to be poured for a toast.[17] Inverting the glass is especially discouraged.[18]
https://en.wikipedia.org/wiki/Toast_(honor)