Caleb knew the routine.  It would be 3 quarts of hot, soapy water.  Once started he would be required to take the whole bag regardless of any cramps.  This had been his regular punishment and as painful as the NMAs were to take, there was something that would get him hard.  He worried that his erection would be noticed and he would be accused of being weird or a pervert.  He wanted to ask his friends if they got NMAs and erections but was too worried they would think he was a freak.