We propose a technique to estimate virtual upper lip (VUL) and virtual lower lip (VLL) trajectories during production of bilabial stop consonants (/p/, /b/) and nasal (/m/). A VUL (VLL) is a hypothetical trajectory below (above) the measured UL (LL) trajectory which could have been achieved by UL (LL) if UL and LL were not in contact with each other during bilabial stops and nasal. Maximum deviation of UL from VUL and its location as well as the range of VUL are used as features, denoted by VUL MD, VUL MDL, and VUL R, respectively. Similarly, VLL MD, VLL MDL, and VLL R are also computed. Analyses of these six features are carried out for /p/, /b/, and /m/ at slow, normal and fast rates based on electromagnetic articulograph (EMA) recordings of VCV stimuli spoken by ten subjects. While no significant differences were observed among /p/, /b/, and /m/ in every rate, all six features except VLL MD were found to drop significantly from slow to fast rates. These six features were also found to perform better in an automatic classification task between slow vs fast rates compared to five baseline features computed from UL and LL comprising their ranges, velocities and minimum distance from each other.