Replying to HELP MY BRO

so my brother is leaving for boot camp in a few weeks and confronted me with an awkward but serious question this morning. While he is a boot camp he is required to wear a white shirt and tighty whiteys when he sleeps. every day he will be waken at random times in the night/morning. WHAT CAN HE DO ABOUT MORNING WOOD? i know its really an awkward question but he needed to ask some one and came to me so i felt like i owed him an answer, please help my bro guys.