A nap taken after someone has consumed any amount of caffeine (i.e. coffee) resulting not in sleep, but blissful rest, while still mildly conscious.
Evelyn: Hey Kaitlyn, how was your coffee nap?
Kaitlyn: It was fantastic I listened to the whole LOVE album, while seeming to float on a cloud.
Evelyn: Awesome! I just had a latte, about to have a coffee nap of my own!