When a guy says “in detail,” it typically means that he wants more specific information or a thorough explanation about a particular topic or situation. This could involve elaborating on certain aspects, providing examples, or clarifying any uncertainties. The phrase suggests that he is interested in understanding the nuances or intricacies of what you’re discussing, so he may be looking for a deeper insight rather than just a surface-level overview. Context matters, so the exact meaning can vary depending on the conversation.