A term for when one is so captivated by something or someone, that their concentration lapses and they drift off in a euphoric daydream.
Usually occurs when bored however, if the source of captivation is strong enough it may happen anywhere.
Olivier: "Yo man, how was your weekend?"
Yugo: "It was great cheers man, I went... *receives text from Emily and drifts into a state of daydreaming bliss*
Olivier: "dude! you're mind flowing again."