Most of the guys masturbated a little bit before in order to proudly present an erected cock at the beginning well knowing they will bravely get their genitals stroked without any restriction, as that was mandatory, without any escape
That was the normal regular working each morning, never mind if sometimes the strokes on our poor balls were terrible, particularly after ejaculation, when our balls were obviously 'emptied' in front of the other young boys, waiting to receive identical treatment!
During three months, normal exercice at the end of sport (Hebert plateau) was regularly done fully nude: each boy had to freely present his genitals to take at least 25 kicks. We stand up, legs largely spreaded, hands on the head, and we have to never complaint when the hard strokes came either from front or from back. Never mind if we ejaculate on air, when our genitals were too much shaked: on the contrary we always were proud to publicly jerk off !