I was in the military, and came home on leave. The only AC was a window model in my sister's room. We wound up sharing a bed. We snuggled, and she started rubbing her ass against my now hard cock. I slid my hand under her shirt and played with her nipple getting it hard. She rolled onto her back. I slid my hand under her panties and fingered her until she came. I pulled her panties off, and ate her pussy until she came again. I was so hard, I slammed my cock into her cunt, and fucked her as hard as i could, going as deep as I could go until I had an amazing orgasm. We fucked for the next two weeks while I was home on leave.