Once he, again, heard the voice of Shiro in his mind, perfectly understanding him Keith returned to being purely freaked out at the situation. He had no idea what to do, say, how to even act at this point, so he sat there in temporary shock. He gulped a bit, trying to communicate with him again, but it didn't come to him. This ability, it seemed to depend purely on how he felt. Whatever intense emotions washed over him, he'd be able to speak to the merman. 

But obviously, even the creature was trying his hardest to speak telepathically. So, Keith shrugged once he regained the least bit of his composure, trying to draw something new on the sand. With his best capabilities, he drew his face. Angry, and Shiro's face right beside it. He drew rays leaving his mind and heading over to Shiro's. Then another drawing where he was grinning and genuinely happy, and rays once again left his head. One last drawing where his face was neutral, and he drew rays but crossed them out with a large 'X'. 

He wasn't even sure if he would understand, or if the human himself could understand properly, but there was no solid way of knowing. He brushed raven hair out of his eyes as he leaned back, looking intensely and carefully onto the eyes of the creature, hoping he could help him make sense of what was going on.