I am teaching two students (X and Y) to program in python. X is a little bit quicker than the Y in grasping the concepts. He likes to help Y figure out what to do with his code, why it isn't working etc. He is very well meaning, but I would like Y to do the work himself. Y is definitely capable of doing it on his own and he will gain a lot more that way. On the other hand it is good to have some interaction between them since discussing issues makes things a lot clearer and more enjoyable. They are both 13 years old. Cheating is not an issue since it is at camp and is not graded.
How do I discourage X from helping Y without making him feel like he did something wrong, and without discouraging him from participating in the future?