The whiteboard plays a crucial role in the day-to-day lives of software architects, as they frequently will organize meetings at the whiteboard to discuss a new architecture, some proposed changes to the architecture, a mismatch between the architecture and the code, and more. While much has been studied about software architects, the architectures they produce, and how they produce them, a detailed understanding of these whiteboards meetings is still lacking. In this paper, we contribute a mixed-methods study involving semi-structured interviews and a subsequent survey to understand the perceptions of software architects on whiteboard architecture meetings. We focus on five aspects: (1) why do they hold these meetings, what is the impact of the experience levels of the participants in these meetings, how do the architects document the meetings, what kinds of changes are made after the meetings have concluded and their results are moved to implementation, and what role do digital whiteboards plays? In studying these aspects, we identify 12 observations related to both technical aspects and social aspects of the meetings. These insights have implications for further research, offer concrete advice to practitioners, provide guidance for future tool design, and suggest ways of educating future software architects.