Ever since I was little, my sister has been overprotective of me, like a real son, and hates the idea of me getting a girlfriend, reading porn, or reading porn. Unable to contain my sexual desire, I bought some really sexy underwear for my sister to wear. She was shy, but she put it on, and it was so erotic that I got a rock hard cock. When my sister noticed my erection, she stared at it with drool dripping from her mouth, so I jokingly asked her if she wanted to lick it, and she suddenly took my dick deep in her throat, so I let her do what she wanted.