Rias and Sona's naked forms glisten under the soft spa lights. The room's warmth is no match for the heat radiating from their bodies. Rias' gaze is a physical touch, tracing Sona's form, igniting her skin. Sona, her breath hitching, can't help but notice Rias' hardening nipples, her own body responding in kind. The spa's bubbles pop quietly, echoing the tension building between them, their bodies aching for release.