Sebastian, their cousin

"Holy fuck, I knew you two were fucking freaks" whistled from the doorway of their room, startling Ben and Sue out of their orgasmic state.

"What the fuck!" Ben exclaimed loudly, his spewing cock slipping from his sister's tight snatch as he turned to see who their intruder was. Even though his cock had swollen up to an impressively thick almost 8 inches, Ben's hands flew to his cock and tried to hide his messy boner.

Standing in the doorway to their room was their cousin Sebastian, one hand pointing his phone at them while the other rubbed and pulled at a growing bulge in his loose shorts.

"Seb, what the fuck are you doing here?!" Shouted an angry and embarrassed Sue, frantically pulling a bedsheet up to cover her cum plastered body. Ben had always gotten along with Sebastian well enough when they were younger but Sue always hated him; she thought he was a creep and a loser.

"Did you two freaks forget that my parents and I were coming for a visit?" Seb sneered at them, his face stretched into a shit-eating grin as he hit a few buttons on his phone.

"Guess I don't really blame ya Ben, I wouldn't remember much if I had this slutty sister to bang when I was home"

"Would you get the fuck out of here!" Sue spit venomously at Sebastian, but Ben had other concerns.

"Dude, did you take a picture of us?"

"Nah man, video; got a nice money shot of you busting a nut in Sue's slutty snatch. Think your mom and dad would be interested in seeing what their twisted kids get up to when they're at work?"

Sue felt herself turn red with fury and embarrassment; she couldn't believe she had been stupid enough to get caught letting Ben fuck her. Ben felt the pit fall out of his stomach and his big cock had deflated with worry; he was more angry that Sebastian was going to fuck up his access to the best pussy in town.

"Unless, of course, you guys were willing to give me a reason to keep my mouth shut" Sebastian sneered at them, rubbing the growing bulge in his loose shorts.

Ben and Sue eyed his bulging shorts with worry. Sebastian was a major creep, but it was looking like he was a creep packing a mighty huge cock.

"What did you have in mind?" They asked.