Quick story!

Had been horny all day so started jacking off before wife gets home.

Hear her come through the door and go into the living room, me being the clever horny guy I am decide it a good idea to go downstairs fully nude and erect to 'surprise' her.

Well, turns out I was the one in for a surprise. No sooner had I entered the room, my full 7.5x6.5 cock proudly on full view I hear a familiar voice...but it wasn't my wife.

"Jeez K, you weren't kidding, that things ginormous"

My SIL was sat 3 feet away from me staring at my cock while my wife was in the kitchen making coffee.

I of course run full pelt out the room and head back upstairs, coming back down a few minutes later, this time fully clothed to apologise.

Fortunately they both found the funny side of things, except now my SIL enjoys making jokes to the both of us about how big my dick is.

Could be worse, could have been the mother in law...