A lot of research effort has been spent on the development of emotion theories and modeling, however, their suitability and applicability to expressions in human computer interaction has not exhaustively been evaluated. Furthermore, investigations concerning the ability of the annotators to map certain expressions onto the developed emotion models is lacking proof. The proposed annotation tool, which incorporates the standard Geneva Emotional Wheel developed by Klaus Scherer and a novel temporal characteristic description feature, is aiming towards enabling the annotator to label expressions recorded in human computer interaction scenarios on an utterance level. Further, it is respecting key features of realistic and natural emotional expressions, such as their sequentiality, temporal characteristics, their mixed occurrences, and their expressivity or clarity of perception. Additionally, first steps towards evaluating the proposed tool, by analyzing utterance annotations taken from two expressive speech corpora, are undertaken and some future goals including the open source accessibility of the tool are given.