Table talk? After-dinner discourse?
I think American families in general are not eating meals together like we used to, maybe not enough to need a word like sobremasa. I thought this translation of sobremesa was interesting.
After the main meal of the day, which usually takes place at around 2 or 3 p.m., the Spanish often linger on at table drinking coffee and/or liqueurs and chatting, playing cards or watching TV before returning to work later in the afternoon. While estar de sobremesa is also occasionally applied to the period after the evening meal, it is more usually taken to mean after lunch, and the sobremesa time band used in TV programme listings applies only to between 2.00 and 5.00 p.m.