Reply when I feel like it.

"Reply when I feel like it."
Means: "I'll never reply. I never feel like it."
Usually the response a guy gets when confronting a female on why she doesn't reply to his messages (and try to work things out).
Can also be undertext if they tell you "I'm busy." which means: "I don't feel like it."

Jason: "I want to fix things, but you never reply, you keep saying you're busy but you're always texting your friends". Sonya: "I'll reply when I feel like it."