In nowadays state of the art VR environments, displayed in CAVEs or HMDs, navigation technics may frequently induce cybersickness or VR-Induced Symptoms and Effects (VRISE), drastically limiting the friendly use of VR environments with no navigation limitations. In two distinct experiments, we investigated acceleration VRISE thresholds for longitudinal and rotational motions and compared 3 different VR systems: 2 CAVEs and a HMD (Oculus Rift DK2). We found that VRISE occur more often and more strongly in case of rotational motions and found no major difference between the CAVEs and the HMD. Based on the obtained thresholds we developed a new "Head Lock" navigation method for rotational motions in a virtual environment in order to generate a “Pseudo AR” mode, keeping fixed visual outside world references. Thanks to a third experiment we have shown that this new metaphor significantly reduces VRISE occurrences and may be a useful base for future natural navigation technics.