CRC-cards are a common lightweight approach to collaborative object-oriented analysis and design. They have been adopted by many educators and trainers to teach object-oriented modelling. In our experience, we have noticed many subtle problems and issues that have largely gone unnoticed in the literature. Two of the major issues are related to the CRC-card role-play as described in the literature. Although CRC-cards are representing classes, they are also utilized as substitutes for the actual objects during the scenario role-play. Furthermore; it is quite difficult to document or trace the scenario role-play. We propose using Role-Play Diagrams (RPDs) to overcome these problems. Our experience so far is quite positive. Novices have fewer problems with role-play activities when using these diagrams. Teaching and learning the new type of diagram adds only little overhead to the overall CRC-approach. Although our improvements specifically target the teaching and learning of object-oriented modelling, we believe that RPDs can be successfully applied in professional software development.