The only thing you can do, anonymous: train your pichu. Your pichu and pidgey’s problem stems from a lack of control. However, if you train him, focusing on control over his electrical powers (through accuracy exercises and the like), you should be able to teach him to manage his abilities on his own.
Alternatively, you’ll bring him closer to evolution, which itself is a good thing because pikachu naturally have better control over their electrical powers than pichu do. (They have larger, more developed electrical sacs, and their tail is better suited for grounding.)