Just in time.

"Aaah. Get out!" Sarah yelled at Adam shaking them both out of their trance.

Adam's face flushed red with embarrassment, when he realized that he must have been staring at his almost fully naked sister for quite some time. His right hand had even moved towards his crotch, but when he looked down he felt relieved, as it hadn't reached his private parts yet. And while he could feel that his penis was rock hard, "thanks" to his size problem, there was no obvious sign to this when looking at his pants. He looked back up at Sarah, who's face was flushed as well, probably equally as red as his own. Yet, somehow he was still **** to move, he couldn't explain how he was so turned on by his own sister.

"Adam! Get out you sick perv!" Sarah yelled again. This time, however, Adam heard a strange tone of command and authority in her voice, and felt the urgent pressure to obey.

"Sorry!" He slowly turned on the spot, stealing last glances at his sister's incredibly sexy body.

"Aaah. And close the door!" Adam obeyed, his feet started to move, and pulled the door behind him shut close.

And just in time for Sarah, as she couldn't hold it in any more. With the crash of the door her cock started to erupt violently, her forceful spurts this time blocked and caught by the wet towel that her cramped hands were still pressing against her body.

As soon as the door was closed the scent of Sarah's precum started to dissipate. But just as Adam's mind began to clear up, he could clearly hear his sister again. The closed door was unable to block the noise of her loud moans. "Was his sister getting off by this whole situation?" Adam's own arousal was undiminished, his penis was rock hard and he himself felt an urgent need to do something about it. To prevent any further embarrassment and to prevent getting caught in a similar predicament as his sister, he quickly moved towards his room, entered it and locked himself in. He wanted to relieve himself without getting disturbed.