Busting Out

She wears a tiny leohex bikini. The black fabric's so small it barely covers anything. Her wrists are tied above her head, straps cutting into her skin. Black hair falls across her face and glasses sit crooked on her nose. The tickling starts light but turns rough fast. Fingers dig into her ribs and she jerks hard against the ropes. The crotch strap slips. It rides up tight between her pussy lips and fights to stay put while her hips twist. She cums without warning. The muscles in her stomach jump, her natural tits bounce, and the strap fights harder. Every laugh breaks into a moan. The more she struggles the more the thin strip of fabric wedges deeper.