Giving stepsister my huge dick

When my stepsister borrowed my phone I didn't know she'd just start browsing through my gallery and see those nudes of her in a shower I secretly made and some pics of my huge cock I made for one of my girlfriends. She got excited and virtually blackmailed me into pulling my cock out, then got on her knees and started sucking. Simple like that! Sure thing we started fucking later and I've been doing her ever since, but that first time was special.