The interaction force between Lund strings contributes to the flow effects in high-multiplicity pp and AA collisions. Hence, it is important to know how much push can this force exert on the strings, whose effects might be observed in the system as a whole. In this talk, we present our shoving mechanism implemented in the Lund string model. This mechanism, along with rope hadronization and colour reconnection processes, makes PYTHIA better equipped to explain collectivity effects in high-multiplicity p-p, p-A and A-A collisions. We present preliminary results of our shoving model on e+e- and p-p angular correlation studies.