In this paper we study group actions on quasi-median graphs, or 'CAT(0) prism complexes', generalising the notion of CAT(0) cube complexes. We consider hyperplanes in a quasi-median graph X and define the contact graph CX for these hyperplanes. We show that CX is always quasi-isometric to a tree, generalising a result of Hagen, and that under certain conditions a group action G↷X induces an acylindrical action G↷CX
Nearby in the stack
, giving a quasi-median analogue of a result of Behrstock, Hagen and Sisto. As an application, we exhibit an acylindrical action of a graph product on a quasi-tree, generalising results of Kim and Koberda for right-angled Artin groups. We show that for many graph products
G
, the action we exhibit is the 'largest' acylindrical action of
G
on a hyperbolic metric space. We use this to show that the graph products of equationally noetherian groups over finite graphs of girth
≥6
are equationally noetherian, generalising a result of Sela.