In this paper, I introduce Sfard's discursive framework to examine secondary-school calculus students' communication during exploratory activities mediated by the use of touchscreen dynamic geometry environments (DGEs). Six pairs of secondary-school students participated in an open-ended task to explore calculus relationships using touchscreen-DGEs. Qualitative data capturing the students' linguistic communication (speech) and hand movements (gestures and dragging) were analysed when the students interacted with the touchscreen-DGEs used during the task. Findings suggest that new forms of communication were mobilised through the act of dragging on a touchscreen-DGE. In particular, routines for comparing, reasoning, conjecturing and verifying emerged within the use of the haptic DGE interface. In this paper, potentials of the touchscreen-DGEs in facilitating new forms of gestural thinking, as well as theoretical and methodological considerations that recognise the changing ways in which the hand and media interact, are discussed.