Inks generally look darker than the ambient (hopefully white) light because most inks generate the color effect by reflecting different wavelengths differently. For ex. blue ink reflects much more around 0,5 micrometers than around 0,7 micrometers. But reflected radiation energy is less than the amount of energy which comes as ambient light onto a painted surface, so colored surface looks dimmer than 100% reflecting pure white.
Fluorescent inks work otherwise. They can convert wavelengths from a wide range to a single wavelength or few wavelengths. In theory fluorescent ink can be as bright as the ambient light or even brighter because the ink material can convert to a certain visible wavelength also infrared or ultraviolet radiation which would be otherwise invisible.
Fluorescent color materials can behave in even more complex way. They can store light energy into long living electron excitation states in bright ambient light conditions and emit it in a certain wavelength during a long time. That makes possible items which look self-illuminating when watched in low ambient light.
You cannot print with ordinary CMYK inks anything which looks fluorescent, because CMYK inks do not make the needed wavelength conversion. You need fluorescent ink. I have never seen them for sale in general stores. I'm afraid printers which can handle them are also kept out of the shelves in stores which aim to sell things to ordinary consumers.
On RGB screen the effect can be simulated. Let the white areas be grey enough and and let all other colors be darker than the one which should look fluorescent. Let it have maximum brightness and saturation.
Someone can claim that it looks like there's a lamp inside the fluorescent looking area. But that's what also real fluorescent inks do. They radiate a certain wavelength or few wavelengths by reusing the radiation energy that the fluorescent material has absorbed.