Inter Caesa et Porrecta
Out of hand. Many things may occur between the cup and lip. (See Cicero: Ad Atticum, v. 18.) Literally, between the slaughter (cæsa) of the sacrifical victim and its being laid (porrecta) on the altar. It was not permitted to speak while the priest struck the animal, nor yet while the sacrifice was being consumed by fire; but between these intervals persons were allowed to talk.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894