The Collaborative International Dictionary of English v.0.48:

Cupper \Cup"per\ (k[u^]p"p[~e]r), n. [Fropm cup.]
   One who performs the operation of cupping.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cupper
    n 1: a cup of tea [syn: cuppa, cupper]