Captive Audience [Commission]
_"my... best friend's sister..."_ he thought, from a distance. it was more of a sound, a noise, intruding on his consciousness than a worry, an actual thought, coming from inside his own mind.
Not Going Extinct 2
Even though he knew he was depositing his eggs directly into his best friend's sister's womb. if it didn't feel so amazing, and jenny had not said 'don't stop', he would have been horrified. but she clearly wanted him to continue. so neither rex yielded.
Campin' with the Girls
Back then he had been a virgin, too, and now he was lying here with his cock up his best friend's sister's butt. the thought would have made him giggle, if he hadn't been to busy enjoying himself.
Home Sweet home
Her best friend's sister moans and pants with pleasure. he feels that his hard penis releases little spurts of pre-cum that get wet from the fur of his stomach.