This... was probably not good. Loras knew in theory what this was- Renly had been good enough to sit him down and have a chat and explain the basic facts to him. What he had failed to mention was how EMBARASSING it was. He'd run off, blushing like a fool. This sort of thing wasn't supposed to happen to knights, was it?
Knights were supposed to rescue and marry fair maidens. They were supposed to fall in love and wear their lady's favor next to their heart. They were definitely NOT supposed to get an erection while helping their knight master out of his armor.
This could be a problem.