Not soon enough

With cum dangling from your lips and your juicy cock half way down your throat a small noise makes you look to your left.

Standing in the doorway is your sister with a look of shock on her face tinged with traces of lust, you just have time to notice how hard her nipples are poking through her shirt when the unthinkable happens.

You erupt for the third time, delicious salty cum pours down your throat, you shudder with orgasmic splendour unable to take your eyes off your sisters face, which has turned from one of shock to one of lust.

"Interesting" She says looking at you, she closes the door behind herself...