Masterpiece, best quality, hyper-realistic, 8k resolution, 32yo adult female, heart-shaped face, eyes rolled back, expression of intense physical strain, plus-size hourglass figure, lying on her side with legs pulled back toward her chest, primary biological male 40yo positioned behind her, (mechanical detail, forceful rhythmic insertion into the anal sphincter:1.3), explicitly stretched gaping rim, visible penetration depth, glistening anal lubrication, skin tension around the perineum, dim industrial lighting with a single harsh spotlight on the contact point, 35mm lens, macro lower torso focus, hyper-realistic skin folding and tension.