Strictly speaking, this connotes only analingus proper, namely the act of kissing & licking the anal region & the perineum. However, vulgarly it is extended to also denote rectolingus, the act of sliding the tongue in & out of the rectum.
In the Catholic & Protestant worlds, the act has traditionally been associated with anti-Christian & Early Christian sects, whence it was ruthlessly suppressed. Thus, in Romance or Roman Catholic Civilization, the act is very rare in the "most Catholic" Hispanic lands of Spain & the Spanish Americas, & is virtually absent in Italy, the centre of Popism. However, this is not the case for the "Least Catholic of the Catholic" lands which were often only partly Catholicized & typically heavily Eastern in spirit. Thus, the act flourished in Orientalized Venice, the "Templar Empire" of Portugal & the Lusophone world, as well as the remote Alpine highlands of the "Templar Republic" of Switzerland & Burgundy. This is shown by the frequent mention of hedralingus in records of Templar initiation rites (where it is a reversion to Early Christian practises) & witchcraft rituals, as well as its prevalence in Luso-American or Brazilian Erotica. In puritanical Protestant Civilizaton (ie. Anglo-Saxon, Germanic & Scandinavian lands), it is historically rare, but is recorded from remote Scotland.
2) "The Portuguese aristocrats, being anti-Catholic Templars, brought the practise of hedralingus to Goa & the Concan. In turn, the local Portughalee & Concani women initiated the visitors to Goa into hedralingus, thereby spreading this practise into the Deccan Sultanates. Portuguese courtezans introduced this to the courts of the Later Timurid Caliphate (Mughal Empire), using it as a yard-stick by which to measure a man's refinement and culture." - Historical account of dissemination of hedralingus into Mughal India.
3) Ravana the big black Shudra Goonda forced Paolo to practise hedralingus on his sweaty Dravidian Jufta (anal crack) in order to establish his dominance over the fair & effeminate Aryan Portughalee Londa (boy).
4) "When the cruel Catholic Spanish tyrant Philip II conquered Portugal, the "Templar Empire", Spain cunningly annexed large parts of Galicia & Lusitania to Spain. At the same time, the fanatical Castilian Inquisitors immediately tried to stamp out hedralingus as well as all other relics of the Knights Templar & Celtic Paganism." - Account of Tyrannical Catholic Spanish Conquest of Templar Portugal