"Usually when our heat periods come around, we have to weather through it without any help from anypony else," she explained. "There is medication for it, but... it's kind of expensive, so a lot of us trained ourselves to resist the urge while we're on duty and relieving it when we're not. But when you showed up, and then volunteered for caretaking duties... Princess Celestia saw an opportunity. I hope you don't hold a grudge against her... or us."