Tissue morphogenesis is governed by mechanical forces generated by cell cytoskeletal networks. It has been shown that subcellular forces are responsible for cell shape changes. Nevertheless cells in a developing organism do not act in isolation: cells contact and adhere one another, and forces are transmitted from cell-to-cell throughout tissues. Understanding how forces are integrated at the tissue level and finally at the full animal scale is nowadays a major challenge that will allow shedding new light on how embryo morphogenesis takes place. In this chapter, I present a new laser-based technique to probe tissue coupling in a living Drosophila embryo. Such technique allows generating mechanical fix boundaries that can eventually impair or modulate cell flows and tissue displacements to probe tissue interaction.