Definition from Wiktionary, the free dictionary
With reference to Tobit 8:1-3, in which Tobias banishes a demon on his wedding-night.
- A wedding night on which consummation of the marriage is postponed (usually in plural).
- 1922, In various parts of Germany and Switzerland continence is observed for three nights after marriage, which are frequently known as the “Tobias nights”; it is believed that otherwise the wedded life of the couple would be unlucky, whereas if they abstain from intercourse the devil will not be able to do any harm. — Edward Westermarck, History of Human Marriage (Kessinger 2003, p.558)