Design sketching is an important and versatile skill for engineering students to master in order to translate their design thoughts effectively onto a visual medium, whether it is to proficiently produce hand-drawn sketches onto paper, seamlessly interact with intelligent sketch-based modeling interfaces, or reap the various educational benefits associated with drawing. Traditional instructional approaches for teaching design sketching are frequently constrained by the availability of experienced human instructors or the lack of supervised learning from self-practice, while relevant intelligent educational applications for sketch instruction have focused more on assessing users´ art drawings or cognitive developmental progress. We introduce PerSketchTivity, an intelligent pen-based computing educational application that not only teaches engineering students how to hone and practice their design sketching skills through stylus-and-touchscreen interaction, but also aiding their motivation and self-regulated learning through real-time feedback. From the qualitative results of our usability tests of our application from eight university student participants of varying skill levels and disciplines, we observed that participants well-rated the usability of the application while also providing valuable feedback to improve the application even further.