Puppy-pile poly refers to polyamorous relationships involving multiple people all of whom have some form of sexual and/or romantic involvement with each other. The implication of the term is that the people involved may all share a sexual or sleeping space bringing to mind a puppy-pile, but this is not necessarily the case in such relationships.
More About Puppy-Pile Poly
Puppy-pile poly is frequently what people who are unfamiliar with polyamory envision when first encountering polyamorous people: folks who are all sexually or romantically entwined. However, this relationship format is only one way to approach polyamory and many choose more structured relationships with clearer distinctions in regards to what everyone’s individual relationships are.