Choreographies describe possible sequences of interactions among a set of agents. We aim to join two lines of research on choreographies: the use of the shuffle on trajectories operator to design more expressive choreographic languages, and the use of models featuring partial orders, to compactly represent concurrency between agents. Specifically, in this paper, we explore the application of the shuffle on trajectories operator to individual posets, and we give a characterisation of shuffles of posets which again yield an individual poset.