After high school, 3 months when I went to basic training in the military.
PS - If anyone ever tells you the military doesn't put salt-peter in the food, they're full of shit! Our barracks was next door to one for female soldiers, a few beauties and they had a Hungarian woman for a drill instructor (she was fucking HOT) and yet, I went three straight months without an erection. Without medication, I don't see how a 17 year old guy can go three straight months without an erection, but I did, so obviously...