Under an assumed name in a tropical region, you meet a young hottie and engage in the well known cliche of sex on the beach. Just before insertion, remove the rubber (without getting caught of course), and proceed to bang away until you blow your load, without pulling out. As you dismount and prepare for departure, grab a handful of sand, throw it in her eyes, and run away laughing hysterically while leaving her blinded, butt-necked, and knocked up. Especially lots of fun when accomplished during the spring break season.
I just sandbagged some girl on the beach, I need the earlier flight!