The Mark (1976)

A slim blonde with long hair gives The Mark a blowjob on a sandy beach, waves crashing behind them. She takes his cock deep, mouth stretched, head bobbing in natural daylight. Later, they’re in a bedroom, both naked, going at it hard — she rides him, then he fucks her from behind, pulling her hair. The brunette shows up too, but mostly watches or joins in briefly, leaning against a wall in a tight top before stripping down. Camera catches the gritty details — facial expressions, the thrust of his hips, cumshot landing on her back. Real casual vibe, like a hookup between people who know each other.