This ritual is a direct reference to Ibn Fadlan's account of crossing paths with people usually identified as being Norse "Vikings" in 921. (Viking is technically a verb. The Norse people would go viking and preform the actions we associate with "Vikings")

Every day the slave-girl arrives in the morning with a large basin containing water, which she hands to her owner. He washes his hands and his face and his hair in the water, then he dips his comb in the water and brushes his hair, blows his nose and spits in the basin. There is no filthy impurity which he will not do in this water. When he no longer requires it, the slave-girl takes the basin to the man beside him and he goes through the same routine as his friend. She continues to carry it from one man to the next until she has gone round everyone in the house, with each of them blowing his nose and spitting, washing his face and hair in the basin.

Online Translation Source: http://www.uib.no/jais/v003ht/03-001-025Montgom1.htm