Gramática: Reciprocal actions, Realidades II, p 224.
Sometimes the reflexive pronouns "se" and "nos" are used to express the idea "(to) each other." These are called reciprocal actions like in "nos vemos."
Los novios se abrazaban y se besaban
Por lo general nos saludábamos con un abrazo y también nos dábamos la mano.
Abrazar, besar, saludar or dar la mano are not reflexive verbs since the actions is done on someone else however, because it happens between two people, the reflexive pronouns se and nos are used here.