Now, we shouldn't go around installing hidden cameras and opening our best friends' doors trying to illegally tape them jacking off, but this scenario is pretty sexy. It's like doing something that's against the rules, and nothing gets us harder than being subversive. Also it taps into the fantasy of discovering a hot guy jerking off and just standing there watching as you feel the boner rise in your jeans. Then he catches your eye and you look at each other nervously as you rub the outline of your hard cock waiting for him to say, "Wanna join?" And then he says it, and you join, and... Excuse us. We have to go jerk off now. Feel free to spy.
·Spying a Friend (gaytube.com)