This ritual involves taking off your clothes and pretending to be wolves, a burping/farting contest, and the use of some sort of hallucinogen I presume.
Yes and no. The specific combination of things is to the best of my knowledge not attested anywhere, but many of the individual parts are.
this sort of ritual of exiting the social world, performing some (bizarre) act, and then returning is a structure generally accepted among religious studies scholars. The framework is derived from the works of Victor Turner and Arnold von Gennep, but in a specifically Norse context has appeared in frameworks by JP Schjødt (a close friend and colleague of Terry Gunnell, who consulted on the film).
the association of this tripartite ritual with wolves specifically has been identified in Völsunga saga, when Sigmundr kills his son Sinfjotli while they are both in the form of wolves, then brings him back to life with a magical herb. It has been argued, though is by no means universally agreed, that this is a several-century-old relic of an actual initial ritual where a father and child act like wolves in order to integrate the boy into the world of adult violence.
the quotes by Heimir throughout the ritual are citations of the eddic poem Hávamál, a long poem that attributes itself to Óðinn. The poem starts off as a list of proverbs and ends with a list of what Óðinn can do with magic spells, and the quotes in the film are all from the first part. Honestly, it can be compared to the Biblical book of Proverbs, in that it is a long series of good advice in navigating a social order.
Tangentially, my personal favorite stanza of that entire poem is one that Amleth and Aurvandil would have done wise to take to heart. It reads "it is better to be alive than to be dead / only the living catch the cow./ I saw flame rise up for the pyre of the rich man/ but he was dead outside before the door." This is the exact opposite of the goal of the ritual, as Aurvandil insists he must die in battle and was prepared to seek it out.