A 30 Second Sam is someone who can't control their urges while in class. They masturbate to random girls in class and doesn't bother to conceal themself. Ususally a 30 Second Sam is someone who is a social out cast and is shunned for constant masturbation. The 30 seconds is how long it takes for him to start masturbating and finish. And they like their own sperm. When the 30 seconds is up, it is common for him wipe it in his hair and smell his finger, with a bright red face.
Person 1= "Why is that kid Masturbating in class?"
Person 2= " Oh he is just a 30 Second Sam"