Graviception, the human sensory perception of gravity and body orientation, plays a fundamental, yet often overlooked, role in how individuals interact with interactive systems. Human-computer interaction has traditionally emphasized visual, auditory, and tactile modalities, while comparatively neglecting the influence of gravity perception on embodiment, attention, motor control, and user experience. This paper draws on the field of biomechanics to examine how graviception can impact interaction, such as the impact of vision and gravity on body movements, especially in immersive, hypogravity environments, mobile contexts of use, and accessibility. By positioning graviception as a first-class concern in embodied interaction, we suggest actionable implications for interaction design that consider graviceptive factors for designers and researchers developing future graviceptive-aware interactive systems. Each implication is described by a short statement, a detailed statement, a rationale, and a series of examples illustrating the impact of graviception on design decisions.