This paper describes a possible dragging experiment in a dynamic geometry environment (DGE) that explores a necessary and sufficient condition for cyclic quadrilateral. The dragging modalities identified by Arzarello, Olivero, Paola, and Robutti (2002) and the functions of variation realized in DGE discussed by Leung (2003) will be used as tools to interpret and analyse the conjecture forming process. We will describe how different dragging strategies in DGE could serve different functions of variation aimed to bring about speculation of mathematical statements (in this case, a necessary and sufficient condition). It is our hope that this paper may initiate further discussion on how functions of variation could instrumentalise (Verillon and Rabardel, 1995) dragging in DGE, within the process of geometric exploration. (Contains 10 figures.)