Short answers, pulled from the story.
Sanskrit texts from the early centuries of the Common Era define sparśa as a precise coming together of three distinct factors. This term means it touches, with touching serving as its salient characteristic. The definition requires the simultaneous presence of a sense organ, a sense object, and sense consciousness.
The Theravada Abhidharma classifies sparśa as one of seven universal mental factors active in every moment of consciousness. Nina van Gorkom writes that phassa arises together with the citta to assist cognition of objects presenting themselves. This mental factor functions to help the mind cognize what appears at the doorways of awareness rather than representing mere physical touch.
Mahayana texts define sparśa differently by emphasizing determination and transformation of controlling power compared to Theravada counterparts. The Abhidharma-samuccaya states that contact provides the basis for feeling when three factors come together. Herbert Guenther explains that this process involves an awareness where pleasant or unpleasant feelings arise upon meeting an object.
Both major Buddhist traditions identify six distinct classes of contact corresponding to different sensory channels including eye-contact, ear-contact, nose-contact, tongue-contact, body-contact, and mind-contact. When the ear sense and a sound object are present, the associated auditory consciousness arises alongside them. Each class operates independently yet follows the same structural pattern of triad formation.
Sparśa occupies the sixth position in the twelve links of dependent origination known as nidānas. Alexander Berzin explains that this link functions during fetal development when distinguishing aggregates operate without feeling aggregates. It is conditioned by the presence of six sense-openings which precede its emergence.